Polymer compositions comprising peptizers, sports equipment comprising such compositions, and method for their manufacture

ABSTRACT

Embodiments of the disclosed polymer composition comprise a first unsaturated polymer or polymer precursor, and an effective amount of a peptizer. The peptizer typically comprises a heteroaryl or a heterocyclic compound, other than morpholine as disclosed in assignee&#39;s prior applications. Disclosed polymer compositions are useful for making sports equipment, such as at least one layer of a golf ball, often a core. Because the compositions are useful for making golf balls, materials commonly known for making such golf balls can be used in combination with the polymer composition. A method for forming a golf ball also is disclosed. The method comprises providing disclosed compositions and then forming at least one component of a golf using the composition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/251,967, filed on Oct. 3, 2011, which is a continuation of U.S.patent application Ser. No. 11/639,871, filed on Dec. 15, 2006, whichclaims the benefit of the earlier filing date of U.S. ProvisionalApplication No. 60/752,475, filed on Dec. 20, 2005. The entiredisclosures of these prior applications are incorporated herein byreference.

FIELD

The present disclosure concerns polymer compositions comprisingpeptizers, particularly nitrogen-based heteroaryl or heterocyclicpeptizers, such as pyridine, diazines and/or triazine compounds, and amethod for making products, such as golf balls, comprising suchcompositions.

BACKGROUND A. Golf Ball Construction and Composition

Modern golf balls generally comprise a core and at least one additionalouter layer. Two-piece balls, having a cover around a solid, oftensingle-piece, spherical rubber core, provide high initial speeds butrelatively low spin rates, and hence perform well for drives and othershots made using woods, but do not perform as well for shots made withshort irons where distance is less important and high spin rate isdesirable. Ball performance can be modified, particularly the traveldistance and the feel transmitted to the golfer through the club, byincluding additional layers between the core and outer cover layer. Athree-piece ball has one additional layer between the core and outercover layer, a four-piece ball has two additional layers between thecore and outer cover layer, and so on.

The compositions that are used to make particular golf ball layers alsocan significantly affect golf ball performance. Compositions can bemodified to vary, for example, polymer hardness, compression, resilienceand/or durability. Most modern golf balls now utilize core compositionsmade from synthetic rubbers based on polybutadiene, especiallycis-1,4-polybutadiene. To vary core properties the polybutadiene oftenis further formulated with crosslinking agents, such as sulfur orperoxides, or with co-crosslinking agents, such as zinc diacrylate. Theweight and hardness of the core may be further adjusted by incorporatingvarious filler materials.

Polyalkenamers, which typically include a linear polymeric component anda significant fraction of cyclic oligomer molecules to lower theirviscosity, also are useful for making golf balls. Compounds of thisclass can be produced in accordance with the teachings of U.S. Pat. Nos.3,804,803, 3,974,092 and 4,950,826, the entire contents of all of whichare incorporated herein by reference. Additional compositions forforming golf balls are disclosed in applicants' copending provisionalapplications, Nos. 60/646,669 and 60/706,562, both of which applicationsare incorporated herein by reference.

B. Golf Ball Compositions Comprising Peptizers

A variety of materials other than polymers or rubber, such as fillersand processing aids, are commonly used to make golf balls. Small amountsof chemical peptizers, for example, have been incorporated into golfball cores to accelerate polybutadiene rubber softening under theinfluence of a mechanical force, heat, or a combination thereof. As usedherein, a peptizer is a compound or composition that inhibitscross-linking during the initial processing of unsaturated polymers, butwhich then participates in the cross-linking of the unsaturated polymerafter cross-linking has commenced. A wider array of active chemicalingredients and fillers can be incorporated into a composition whenpeptizers are used relative to compositions formulated withoutpeptizers. Peptizers also facilitate processing compositions, such as bylowering processing temperatures.

Particular peptizers are known for making polymer compositions,including golf ball compositions. For example, U.S. Pat. No. 4,955,966,states that the “rubber composition of the present invention may beincorporated with various known additives, for example, vulcanizationaccelerator, vulcanization retarder, antioxidant, plasticizer, peptizer,tackifier, antitack agent, sponging agent, dispersant, dusting agent,mold release agent, solvent, softening agent and the like.” The '966patent, column 10, lines 3-9, (emphasis added). This is the onlydisclosure provided by the '966 patent concerning peptizers. Themajority of patents that disclose using peptizers to make golf ballcompositions do not provide information or otherwise identify particularpeptizers useful for making such compositions.

A few patent documents do disclose specific peptizer compounds. Forexample, U.S. Pat. No. 5,948,862 discloses using diphenyl disulfidepeptizers. U.S. Pat. Nos. 6,569,037, 6,692,379 and 6,905,423 discloseusing zinc salts of pentachlorothiophenol. The '423 patent specificallystates that:

-   -   The soft intermediate layer may also contain additives, fillers,        thickeners, or a combination thereof, to adjust the specific        gravity of the layer to alter various golf ball properties as        needed or desired. “RENACIT” 7 is a peptizer produced by Miles,        Inc. of Pittsburgh, Pa., that is a pentachlorothiophenol mixture        containing Kaolin, quartz, and mineral oil. Materials such as        “RENACIT” 7 can be used to alter the properties of the inner        surface of the mantle layer. Specifically, it can be used to        soften the inner surface.        The '423 patent, column 12, lines 32-39.

TaylorMade® also has several issued patents and patent applications thatdiscuss using peptizers for making golf ball compositions, includingU.S. application Ser. No. 10/926,509, entitled “Golf Balls IncorporatingNanofillers,” and U.S. application Ser. Nos. 10/662,619, 10/662,626,10/662,628 and 10/662,719, entitled “Golf Balls Incorporating Peptizersand Method of Manufacture.” Each of these prior TaylorMade® applicationsis incorporated herein by reference. These prior applications state, forexample, that:

-   -   Peptizers can be defined as chemicals that inhibit cross-linking        during the processing of unsaturated polymers. The peptizer can        further participate in the cross-linking of the unsaturated        polymer when cross-linking does begin. The peptizer comprises an        organic sulfur compound and/or its metal or non-metal salt.        Examples of the organic sulfur compound include: thiophenols,        such as pentachlorothiophenol and its metal and non-metal salts,        4-butyl-o-thiocresol, 4 t-butyl-p-thiocresol, and        2-benzamidothiophenol; thiocarboxylic acids, such as thiobenzoic        acid; 4,4′ dithio dimorpholine; and, sulfides, such as dixylyl        disulfide, dibenzoyl disulfide; dibenzothiazyl disulfide;        di(pentachlorophenyl)disulfide; dibenzamido diphenyldisulfide        (DBDD), and alkylated phenol sulfides, such as VULTAC marketed        by Atofina Chemicals, Inc. of Philadelphia, Pa. Examples of the        metal salts of an organic sulfur compound include zinc salts of        the above-mentioned thiophenols and thiocarboxylic acids.        Examples of non-metal salts of an organic sulfur compound        include the amine or ammonium salts of the above-mentioned        thiophenols and thiocarboxylic acids. Preferred peptizers        include pentachlorothiophenol, its metal salts, and its        non-metal salts, and dibenzamido diphenyldisulfide. Peptizers        can be used alone or in an admixture of two or more peptizers.

SUMMARY

As far as the inventors know, no one has made compositions, particularlygolf ball compositions, that comprise peptizers disclosed herein, suchas nitrogen-based, heteroaryl or heterocyclic peptizers. Compositions ofthe present invention provide added flexibility for formulating golfball compositions and for making golf balls having physical propertiesthat differ from golf balls that currently can be made.

Embodiments of the disclosed polymer composition comprise a firstunsaturated polymer or polymer precursor, and an effective amount of apeptizer. The peptizer typically comprises a heteroaryl or aheterocyclic compound, other than morpholine as disclosed in assignee'sprior applications. The peptizer also may be acyclic. Heterocyclic andacyclic compounds typically comprise an unsaturated compound, and evenmore typically are conjugated compounds having at least one heteroatom,such as nitrogen, oxygen, or sulfur, and most typically nitrogen,conjugated to a functional group bearing a sulfur atom, such as asulfhydryl group. All possible combinations of such peptizers also canbe used to make suitable compositions. Moreover, the composition alsomay comprise at least one additional peptizer known prior to the presentinvention, such as organic sulfur compounds, metal salts of organicsulfur compounds, non-metal salts of organic sulfur compounds, andcombinations thereof.

The peptizer may be a heteroaryl or heterocyclic compound having aformula

where A is a heteroatom, m is from 1 to n, where n is the number ofatoms in the ring, and R is optionally present and is hydrogen or analiphatic group. The peptizer may have more than one ring, and each ringtypically has from about 3 atoms to at least about 10 ring atoms, moretypically from about 4 to about 7 ring atoms, and preferred compoundshave at least one ring having 5 or 6 ring atoms. For peptizerscomprising more than one ring, each ring may have the same or adifferent number of atoms per ring. Examples of specific classes ofpeptizers include peptizers based on indole, quinoline, isoquinoline,pyridine, purine, pyrimidine, diazine, triazine, carbazole, orcombinations of such peptizers.

A more specific structural chemical formula depicting disclosedsulfur-substituted heteroaryl or heterocyclic peptizers compounds is asfollows

where A is a heteroatom, e.g., nitrogen, oxygen or sulfur, preferablynitrogen, m is from 1 to n, where n is the number of atoms in the ring,R₁-R₂ are the same or different, and are independently hydrogen, sulfurand aliphatic groups, and R₃ is optionally present and is hydrogen or analiphatic group.

Disclosed peptizers can include additional functional groups. Suchsubstituted compounds also typically satisfy a formula

where A again is a heteroatom, m is from 1 to n, where n is the numberof atoms in the ring, R₁-R₂ are the same or different, and areindependently hydrogen, sulfur, and aliphatic groups, R₃ is optionallypresent and is hydrogen or an aliphatic group, R₄ and R₅ are the same ordifferent, and are independently hydrogen, halogen, and aliphaticgroups.

Disclosed peptizers may be heteroaryl compounds, often nitrogen-basedcompounds having a formula

A more specific structural formula is as follows

where V-Z independently are carbon or heteroatoms. Such peptizers alsooptionally may include at least one R group selected from hydrogen,halogen, oxygen-bearing moieties, sulfur-bearing moieties, aliphaticgroups, and combinations thereof. Likewise, R₂-R₆ independently arehydrogen, halogen, oxygen-bearing moieties, sulfur-bearing moieties, andaliphatic groups, most typically hydrogen, halogen, particularlychlorine, and sulfur-bearing moieties. Certain disclosed compounds haveat least one of R₂-R₆=—SH, and at least one of the remainingR₂-R₆=halogen, more typically the remaining R₂-R₆ are halogen.

Pyridine-based peptizers can be depicted using a formula

where R₁-R₅ are independently hydrogen, halogen, typically chlorine,oxygen-bearing moieties, sulfur-bearing moieties, such as sulfhydryl ordisulfides, and aliphatic groups.

Heteroaryl compounds having two or more heteroatoms, such as nitrogen,also can function as suitable peptizers. Examples of peptizers havingtwo nitrogen atoms include

where R₁—R₅ are independently hydrogen, halogen, oxygen-bearingmoieties, sulfur-bearing moieties, and aliphatic groups.

Examples of heteroaryl compounds having 3 ring nitrogen atoms have aformula

where R₂, R₄ and R₆ independently are hydrogen, halogen, oxygen-bearingmoieties, sulfur-bearing moieties and aliphatic groups. Preferredcompounds typically have at least one halogen, typically chlorine, andalso typically include a sulfur-bearing moiety, such as a sulfhydrylgroup.

The peptizer may be used as a salt. The salt may be a metal salt, anon-metal salt, such as an ammonium salt, a mixed metal and non-metalsalt, and combinations thereof.

Suitable polymer compositions often include unsaturated syntheticrubber, natural rubber, a polyalkenamer, an olefinic thermoplasticelastomer, and combinations thereof. Examples of unsaturated polymersinclude, without limitation, 1,2-polybutadiene, cis-1,4-polybutadiene,trans-1,4-polybutadiene, cis-polyisoprene, trans-polyisoprene,polychloroprene, polybutylene, styrene-butadiene rubber,styrene-butadiene-styrene block copolymer, styrene-isoprene-styreneblock copolymer, nitrile rubber, silicone rubber, polyurethane, ormixtures thereof. Preferred poly(1,4-butadiene) rubbers contain at least40 mol % cis-1,4 bonds, and even more preferably include at least 80 mol% cis-1,4 bonds.

The polymer composition according to claim 1 can include at least oneadditional polymer as well. This additional polymer or polymers may beincluded after any crosslinking occurs, or can be blended with the atleast a second polymer. Thus, the polymer composition may comprise fromabout 1 to about 99 weight percent of an additional thermoplastic orthermoset polymeric material, including without limitation, syntheticand natural rubbers, thermoset polyurethanes and thermoset polyureas,unimodal ethylene/carboxylic acid copolymers, unimodalethylene/carboxylic acid/carboxylate terpolymers, bimodalethylene/carboxylic acid copolymers, bimodal ethylene/carboxylicacid/carboxylate terpolymers, unimodal ionomers, bimodal ionomers,modified unimodal ionomers, modified bimodal ionomers, polyalkenamers,crosslinked polyalkenamers, polyisoprene rubber, styrene-butadienerubber, polyurethane ionomer, thermoplastic polyurethanes, thermoplasticpolyureas, polyamides, copolyamides, polyesters, copolyesters,polycarbonates, polyolefins, halogenated polyolefins, halogenatedpolyethylenes, polyphenylene oxide, polyphenylene sulfide, diallylphthalate polymer, polyimides, polyvinyl chloride, polyamide-ionomer,polyvinyl alcohol, polyarylate, polyacrylate, polyphenylene ether,impact-modified polyphenylene ether, polystyrene, high impactpolystyrene, acrylonitrile-butadiene-styrene copolymerstyrene-acrylonitrile (SAN), acrylonitrile-styrene-acrylonitrile,styrene-maleic anhydride (S/MA) polymer, styrenic copolymer,functionalized styrenic copolymer, functionalized styrenic terpolymer,styrenic terpolymer, cellulose polymer, liquid crystal polymer (LCP),ethylene-propylene-diene terpolymer (EPDM), ethylene-vinyl acetatecopolymers (EVA), ethylene-propylene copolymer, ethylene vinyl acetate,polyurea, polysiloxane, a compound having a general formula(R₂N)_(m)—R′-(X(O)_(n)OR_(y))_(m), wherein R is selected from the groupconsisting of hydrogen, one or more C₁-C₂₀ aliphatic systems, one ormore cycloaliphatic systems, one or more aromatic systems, R′ is abridging group comprising one or more unsubstituted C₁-C₂₀ straightchain or branched aliphatic or alicyclic groups, one or more substitutedstraight chain or branched aliphatic or alicyclic groups, one or morearomatic groups, one or more oligomers each containing up to 12repeating units, and when X is C or S or P, m is 1-3, when X=C, n=1 andy=1, when X=S, n=2 and y=1, and when X=P, n=2 and y=2, and any and allcombinations of such materials. Preferred polymer composition ofteninclude 80% by weight or greater poly(1,4-butadiene) rubber.

Polymer compositions also typically include at least one cross-linkingagent. The cross-linking agent often is a peroxide, and can be aprimary, secondary, or tertiary aliphatic, alicyclic or aromaticperoxide, and also may include plural peroxy groups. Specific examplesof suitable cross-linking agents include diacetyl peroxide,di-tert-butyl peroxide, dibenzoyl peroxide, dicumyl peroxide,2,5-dimethyl-2,5-di(benzoylperoxy)hexane,1,4-bis-(tert-butylperoxyisopropyl)benzene, tert-butylperoxybenzoate,2,5-dimethyl-2,5-di-(tert-butylperoxy)hexyne,1,1-bis(tert-butylperoxy)-3,3,5-tri-methylcyclohexane,di-(2,4-dichlorobenzoyl)peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 1,4-di-(2-tert-butyl peroxyisopropyl)benzene, tert-butylperbenzoate, tert-butyl cumyl peroxide, and combinations thereof.

Disclosed polymer compositions are useful for making sports equipment,such as golf balls. Thus, disclosed embodiments also concern a polymercomposition useful for making at least one layer of a golf ball, wherethe composition comprises an unsaturated polymer or polymer precursor, across-linking agent, and an effective amount of a peptizer comprising aheteroaryl compound, a heterocycle other than morpholine, an organicsulfur compound comprising at least one heteroatom conjugated to afunctional group bearing a sulfur atom, and combinations thereof. Thecomponents of the composition can have the attributes discussed abovefor such compositions. The golf ball layer often is a core.

Because the compositions are useful for making golf balls, materialscommonly known for making such golf balls can be used in combinationwith the polymer composition, such as a fiber, a filler, a cross-linkingagent selected from sulfur compounds, peroxides, azides, maleimides,e-beam radiation, gamma-radiation, a co-cross-linking agent comprisingzinc or magnesium salts of an unsaturated fatty acid having from about 3to about 8 carbon atoms, a base resin, a peptizer known prior to thepresent application, an accelerator, a UV stabilizer, a photostabilizer,a photoinitiator, a co-initiator, an antioxidant, a colorant, adispersant, a mold release agent, a processing aid, a density adjustingfiller, a nanofiller, an inorganic filler, an organic filler, andcombinations thereof. Examples of fillers include precipitated hydratedsilica, limestone, clay, talc, asbestos, barytes, glass fibers, aramidfibers, mica, calcium metasilicate, barium sulfate, zinc sulfide,lithopone, silicates, silicon carbide, diatomaceous earth, calciumcarbonate, magnesium carbonate, barium carbonate, calcium sulfate,magnesium sulfate, barium sulfate, tungsten, steel, copper, cobalt,iron, metal alloys, tungsten carbide, zinc oxide, calcium oxide, bariumoxide, titanium dioxide, metal stearates, particulate carbonaceousmaterials, nanofillers and any and all combinations thereof. Examples ofnanofiller include inorganic clays selected from the group consisting ofhydrotalcite, phyllosilicate, saponite, hectorite, beidellite,stevensite, vermiculite, halloysite, mica, montmorillonite,micafluoride, octosilicate, and combinations thereof. The nanofiller maybe surface treated with a compatibilizer selected from the groupconsisting of hydroxy-, thiol-, amino-, epoxy-, carboxylic acid-,ester-, amide-, and siloxy-group containing compounds, oligomers,polymers and combinations thereof. The nanofiller may be intercalatedwithin the polymeric material or exfoliated within the polymer.

Golf balls made according to the present invention typically have a PGAcompression of from about 30 to about 190, more typically from about 40to about 160, even more typically from about 50 to about 130, and mosttypically from about 60 to about 100.

A person of ordinary skill in the art also will appreciate that the sizeof golf balls that can be made using the disclosed compositions canvary. For example, for golf balls having one or more intermediate layersand a cover layer, the one or more intermediate layers or cover layermay have a thickness of from about 0.01 to about 0.20 inch, moretypically from about 0.02 to about 0.15 inch, even more typically fromabout 0.03 to about 0.1 inch, and most typically from about 0.03 toabout 0.06 inch. The hardness of disclosed golf balls layers also canvary, so that one or more intermediate layers or cover layer may have aShore D hardness of greater than about 25, typically greater than about30, and even more typically about 40 or greater.

Disclosed golf balls also may have various cover layers. For example,the cover layer may be formed from a composition comprising a reactionproduct of (a) diol(s), polyol(s), or combinations thereof; (b)diisocyanate(s), polisocyanate(s), or combinations thereof; (c)diamine(s), polyamine(s), or combinations thereof; or any combinationsof (a), (b), and (c). Moreover, the cover layer may be formed by amethod comprising mixing at least one component A that is a monomer,oligomer, prepolymer, or polymer comprising at least 5% by weight ofanionic functional groups; at least one component B that is a monomer,oligomer, prepolymer, or polymer comprising less by weight of anionicfunctional groups than the weight percentage of anionic functionalgroups of the at least one component A; and at least one component Cthat is a metal cation, thereby forming a first composition. The firstcomposition is melt-processed to produce a reaction product of theanionic functional groups of the at least one component A and the atleast one component C to form the polymer blend composition, wherein thepolymer blend composition incorporates an in-situ-formedpseudo-crosslinked network of the at least one component A in thepresence of the at least one component B.

A method for forming a golf ball also is disclosed. The method comprisesproviding a composition comprising an unsaturated polymer materialuseful for forming a golf ball and an effective amount of peptizercomprising a heteroaryl compound, a heterocycle other than morpholine,an organic sulfur compound comprising at least one heteroatom conjugatedto a functional group bearing a sulfur atom, and combinations thereof.At least one component of a golf ball is then formed using thecomposition.

The foregoing and other objects, features, and advantages of theinvention will become more apparent from the following detaileddescription, which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross section of a two-piece golf ball.

FIG. 2 is a schematic cross section of a three-piece golf ball.

DETAILED DESCRIPTION I. Introduction and Definitions

The following definitions, presented in alphabetical order, are providedto aid the reader, and are not intended to provide term definitions thatwould be narrower than would be understood by a person of ordinary skillin the art of golf ball composition and manufacture.

Any numerical values recited herein include all values from the lowervalue to the upper value. All possible combinations of numerical valuesbetween the lowest value and the highest value enumerated herein areexpressly included in this application.

The terms “aryl” and “heteroaryl” as used herein refer to any arylgroup, which optionally can be substituted, or any “heteroaryl” group,which also optionally can be substituted, and includes, by way ofexample and without limitation, phenyl, biphenyl, indenyl, naphthyl(1-naphthyl, 2-naphthyl), N-hydroxytetrazolyl, N-hydroxytriazolyl,N-hydroxyimidazolyl, anthracenyl (1-anthracenyl, 2-anthracenyl,3-anthracenyl), thiophenyl (2-thienyl, 3-thienyl), furyl (4-furyl,3-furyl), indolyl, oxadiazolyl, isoxazolyl, quinazolinyl, fluorenyl,xanthenyl, isoindanyl, benzhydryl, acridinyl, thiazolyl, pyrrolyl(2-pyrrolyl), pyrazolyl (3-pyrazolyl), imidazolyl (1-imidazolyl,2-imidazolyl, 4-imidazolyl, 5-imidazolyl), triazolyl(1,2,3-triazol-1-yl, 1,2,3-triazol-2-yl 1,2,3-triazol-4-yl,1,2,4-triazol-3-yl), oxazolyl (2-oxazolyl, 4-oxazolyl, 5-oxazolyl),thiazolyl (2-thiazolyl, 4-thiazolyl, 5-thiazolyl), pyridyl (2-pyridyl,3-pyridyl, 4-pyridyl), pyrimidinyl (2-pyrimidinyl, 4-pyrimidinyl,5-pyrimidinyl, 6-pyrimidinyl), pyrazinyl, pyridazinyl (3-pyridazinyl,4-pyridazinyl, 5-pyridazinyl), quinolyl (2-quinolyl, 3-quinolyl,4-quinolyl, 5-quinolyl, 6-quinolyl, 7-quinolyl, 8-quinolyl), isoquinolyl(1-isoquinolyl, 3-isoquinolyl, 4-isoquinolyl, 5-isoquinolyl,6-isoquinolyl, 7-isoquinolyl, 8-isoquinolyl), benzo[b]furanyl(2-benzo[b]furanyl, 3-benzo[b]furanyl, 4-benzo[b]furanyl,5-benzo[b]furanyl, 6-benzo[b]furanyl, 7-benzo[b]furanyl),2,3-dihydro-benzo[b]furanyl (2-(2,3-dihydro-benzo[b]furanyl),3-(2,3-dihydro-benzo[b]furanyl), 4-(2,3-dihydro-benzo[b]furanyl),5-(2,3-dihydro-benzo[b]furanyl), 6-(2,3-dihydro-benzo[b]furanyl),7-(2,3-dihydro-benzo[b]furanyl), benzo[b]thiophenyl(2-benzo[b]thiophenyl, 3-benzo[b]thiophenyl, 4-benzo[b]thiophenyl,5-benzo[b]thiophenyl, 6-benzo[b]thiophenyl, 7-benzo[b]thiophenyl),2,3-dihydro-benzo[b]thiophenyl, (2-(2,3-dihydro-benzo[b]thiophenyl),3-(2,3-dihydro-benzo[b]thiophenyl), 4-(2,3-dihydro-benzo[b]thiophenyl,5-(2,3-dihydro-benzo[b]thiophenyl), 6-(2,3-dihydro-benzo[b]thiophenyl),7-(2,3-dihydro-benzo[b]thiophenyl), indolyl (1-indolyl, 2-indolyl,3-indolyl, 4-indolyl, 5-indolyl, 6-indolyl, 7-indolyl), indazole(1-indazolyl, 3-indazolyl, 4-indazolyl, 5-indazolyl, 6-indazolyl,7-indazolyl), benzimidazolyl (1-benzimidazolyl, 2-benzimidazolyl,4-benzimidazolyl, 5-benzimidazolyl, 6-benzimidazolyl, 7-benzimidazolyl,8-benzimidazolyl), benzoxazolyl (1-benzoxazolyl, 2-benzoxazolyl),benzothiazolyl (1-benzothiazolyl, 2-benzothiazolyl, 4-benzothiazolyl,5-benzothiazolyl, 6-benzothiazolyl, 7-benzothiazolyl), carbazolyl(1-carbazolyl, 2-carbazolyl, 3-carbazolyl, 4-carbazolyl),5H-dibenz[b,f]azepine (5H-dibenz[b,f]azepin-1-yl,5H-dibenz[b,f]azepine-2-yl, 5H-dibenz[b,f]azepine-3-yl,5H-dibenz[b,f]azepine-4-yl, 5H-dibenz[b,f]azepine-5-yl,10,11-dihydro-5H-dibenz[b,f]azepine(10,11-dihydro-5H-dibenz[b,f]azepine-1-yl,10,11-dihydro-5H-dibenz[b,f]azepine-2-yl.

The term “bimodal polymer” refers to a polymer comprising two mainfractions and more specifically to the form of the polymer's molecularweight distribution curve, i.e., the appearance of the graph of thepolymer weight fraction as a function of its molecular weight. When themolecular weight distribution curves from these fractions aresuperimposed onto the molecular weight distribution curve for the totalresulting polymer product, that curve will show two maxima or at leastbe distinctly broadened in comparison with the curves for the individualfractions. Such a polymer product is called bimodal. The chemicalcompositions of the two fractions may be different.

“Conjugated” refers to an organic compound containing two or more sitesof unsaturation (e.g., carbon-carbon double bonds, carbon-carbon triplebonds, and sites of unsaturation comprising atoms other than carbon,such as nitrogen) separated by a single bond.

As used herein, the term “core” is intended to mean the elastic centerof a golf ball, which may have a unitary construction. Alternatively thecore itself may have a layered construction, e.g. having a spherical“center” and additional “core layers,” with such layers being made ofthe same material or a different material from the core center.

The term “cover” is meant to include any layer of a golf ball thatsurrounds the core. Thus a golf ball cover may include both theoutermost layer and also any intermediate layers, which are disposedbetween the golf ball center and outer cover layer. “Cover” may be usedinterchangeably with the term “cover layer”.

A “fiber” is a general term and the definition provided by EngineeredMaterials Handbook, Vol. 2, “Engineering Plastics”, published by A.S.M.International, Metals Park, Ohio, USA, is relied upon to refer tofilamentary materials with a finite length that is at least 100 timesits diameter, which typically is 0.10 to 0.13 mm (0.004 to 0.005 in.).Fibers can be continuous or specific short lengths (discontinuous),normally no less than 3.2 mm (⅛ in.). Although fibers according to thisdefinition are preferred, fiber segments, i.e., parts of fibers havinglengths less than the aforementioned also are considered to beencompassed by the invention. Thus, the terms “fibers” and “fibersegments” are used herein. “Fibers or fiber segments” and “fiberelements” are used to encompass both fibers and fiber segments.Embodiments of the golf ball components described herein may includefibers including, by way of example and without limitation, glassfibers, such as E fibers, Cem-Fil filament fibers, and 204 filamentstrand fibers; carbon fibers, such as graphite fibers, high moduluscarbon fibers, and high strength carbon fibers; asbestos fibers, such aschrysotile and crocidolite; cellulose fibers; aramid fibers, such asKevlar, including types PRD 29 and PRD 49; and metallic fibers, such ascopper, high tensile steel, and stainless steel. In addition, singlecrystal fibers, potassium titanate fibers, calcium sulphate fibers, andfibers or filaments of one or more linear synthetic polymers, such asTerylene, Dacron, Perlon, Orion, Nylon, including Nylon type 242, arecontemplated. Polypropylene fibers, including monofilament andfibrillated fibers are also contemplated. Golf balls according to thepresent invention also can include any combination of such fibers.Fibers used in golf ball components are described more fully in Kim etal. U.S. Pat. No. 6,012,991, which is incorporated herein by reference.

The term “fully-interpenetrating network” refers to a network thatincludes two independent polymer components that penetrate each other,but are not covalently bonded to each other.

In the case of a ball with two intermediate layers, the term “innerintermediate layer” may be used interchangeably herein with the terms“inner mantle” or “inner mantle layer” and is intended to mean theintermediate layer of the ball positioned nearest to the core.

The term “intermediate layer” may be used interchangeably with “mantlelayer,” “inner cover layer” or “inner cover” and is intended to mean anylayer(s) in a golf ball disposed between the core and the outer coverlayer.

The term “(meth)acrylate” is intended to mean an ester of methacrylicacid and/or acrylic acid.

The term “(meth)acrylic acid copolymers” is intended to mean copolymersof methacrylic acid and/or acrylic acid.

A “nanocomposite” is defined as a polymer matrix having nanofillerwithin the matrix. Nanocomposite materials and golf balls madecomprising nanocomposite materials are disclosed in Kim et al., U.S.Pat. No. 6,794,447, and U.S. Pat. No. 5,962,553 to Ellsworth, U.S. Pat.No. 5,385,776 to Maxfield et al., and U.S. Pat. No. 4,894,411 to Okadaet al., which are incorporated herein by reference in their entirety.Inorganic nanofiller materials generally are made from clay, and may becoated by a suitable compatibilizing agent, as discussed below infurther detail. The compatibilizing agent allows for superior linkagebetween inorganic and organic material, and it also can account for thehydrophilic nature of the inorganic nanofiller material and the possiblyhydrophobic nature of the polymer. Nanofiller particles typically, butnot necessarily, are approximately 1 nanometer (nm) thick and from about100 to about 1,000 nm across, and hence have extremely high surfacearea, resulting in high reinforcement efficiency to the material at lowparticle loading levels. The sub-micron-sized particles enhance materialproperties, such as the stiffness of the material, without increasingits weight or opacity and without reducing the material'slow-temperature toughness. Materials incorporating nanofiller materialscan provide these property improvements at much lower densities thanthose incorporating conventional fillers.

Nanofillers can disperse within a polymer matrix in three ways. Thenanofiller may stay undispersed within the polymer matrix. Undispersednanofillers maintain platelet aggregates within the polymer matrix andhave limited interaction with the polymer matrix. As the nanofillerdisperses into the polymer matrix, the polymer chains penetrate into andseparate the platelets. When viewed by transmission electron microscopyor x-ray diffraction, the platelet aggregates are expanded relative toundispersed nanofiller. Nanofillers at this dispersion level arereferred to as being intercalated. A fully dispersed nanofiller is saidto be exfoliated. An exfoliated nanofiller has the platelets fullydispersed throughout the polymer matrix; the platelets may be dispersedunevenly but preferably are dispersed substantially evenly.

Nanocomposite materials are materials incorporating from about 0.1% toabout 20%, preferably from about 0.1% to about 15%, and most preferablyfrom about 0.1% to about 10% nanofiller potentially reacted into andpreferably substantially evenly dispersed through intercalation orexfoliation into the structure of an organic material, such as apolymer, to provide strength, temperature resistance, and other propertyimprovements to the resulting composite. Descriptions of particularnanocomposite materials and their manufacture can be found in U.S. Pat.No. 5,962,553 to Ellsworth, U.S. Pat. No. 5,385,776 to Maxfield et al.,and U.S. Pat. No. 4,894,411 to Okada et al. Examples of nanocompositematerials currently marketed include M1030D, manufactured by UnitikaLimited, of Osaka, Japan, and 1015C2, manufactured by UBE America of NewYork, N.Y.

When nanocomposites are blended with other polymer systems, thenanocomposite may be considered a type of nanofiller concentrate.However, a nanofiller concentrate may be more generally a polymer intowhich nanofiller is mixed; a nanofiller concentrate does not requirethat the nanofiller has reacted and/or dispersed evenly into the carrierpolymer. When used in the manufacture of golf balls, nanocompositematerials can be blended effectively into ball compositions at a typicalweight percentage, without limitation, of from about 1% to about 50% ofthe total composition used to make a golf ball component, such as acover or core, by weight.

The term “outer cover layer” is intended to mean the outermost coverlayer of the golf ball on which, for example, the dimple pattern, paintand any writing, symbol, etc. is placed. If, in addition to the core, agolf ball comprises two or more cover layers, only the outermost layeris designated the outer cover layer. The remaining layers may bedesignated intermediate layers. The term outer cover layer isinterchangeable with the term “outer cover”.

In the case of a ball with two intermediate layers, the term “outerintermediate layer” may be used interchangeably herein with the terms“outer mantle” or “outer mantle layer” and is intended to mean theintermediate layer of the ball which is disposed nearest to the outercover layer.

“Peptizers” are chemical(s) or compositions that have been used byrubber compounders to facilitate the processing of natural or syntheticrubbers and other difficult-to-process high viscosity elastomers duringmilling and mastication. High shear mixing of elastomers or rubbersbrings can cause chemical degradation or scission of some of the polymerchains into two or several parts and each chain end is either a freeradical or the result of disproportionation of free radicals. This chainscission mechanism thus brings about an initial reduction in the numberof higher molecular weight species. In the absence of a peptizer, thesefree radicals quickly recombine without a significant reduction inviscosity. However, in the presence of peptizers, a peroxide freeradical is formed which is more stable than the original radical, withthe result that the viscosity is reduced quite significantly. Peptizersare chemical(s) or compositions that inhibit polymer cross-linking, mosttypically cross-linking of unsaturated polymers, but which canparticipate in polymer cross-linking after cross-linking is initiated.

The term “polyalkenamer” is used interchangeably herein with the term“polyalkenamer rubber” and means a polymer of one or more alkenes,including cycloalkenes, having from 5-20, preferably 5-15, mostpreferably 5-12 ring carbon atoms. The polyalkenamers may be prepared byany suitable method including ring opening metathesis polymerization ofone or more cycloalkenes in the presence of organometallic catalysts asdescribed in U.S. Pat. Nos. 3,492,245, and 3,804,803, the entirecontents of both of which are incorporated herein by reference.

“Polymer precursor material” refers to any material that can be furtherprocessed to form a final polymer material of a manufactured golf ball,such as, by way of example and not limitation, monomers that can bepolymerized, or a polymerized or partially polymerized material that canundergo additional processing, such as crosslinking.

The term “pseudo-crosslinked network” refers to materials that have crosslinking, but, unlike chemically vulcanized elastomers,pseudo-crosslinked networks are formed in-situ, not by covalent bonds,but instead by ionic clustering of the reacted functional groups, whichclustering may disassociate at elevated temperatures.

The term “semi-interpenetrating network” refers to a network thatincludes at least one polymer component that is linear or branched andinterspersed in the network structure of at least one of the otherpolymer components.

A “thermoplastic material” is generally defined as a material that iscapable of softening or fusing when heated and of hardening again whencooled. Thermoplastic polymer chains often are not cross-linked, but theterm “thermoplastic” as used herein may refer to materials thatinitially act as thermoplastics, such as during an initial extrusionprocess or injection molding process, but which also may be crosslinked,such as during a compression molding step to form a final structure.

The term “unimodal polymer” refers to a polymer comprising one mainfraction and more specifically to the form of the polymer's molecularweight distribution curve, i.e., the molecular weight distribution curvefor the total polymer product shows only a single maximum.

II. Golf Ball Composition and Construction

FIG. 1 illustrates a two-piece golf ball 10 comprising a solid center orcore 12, and an outer cover layer 14. Golf balls also typically includeplural dimples 16 formed in the outer cover and arranged in variousdesired patterns.

FIG. 2 illustrates a 3-piece golf ball 20 comprising a core 22, anintermediate layer 24 and an outer cover layer 26. Golf ball 20 alsotypically includes plural dimples 28 formed in the outer cover layer 26and arranged in various desired patterns. Although FIGS. 1 and 2illustrate only two- and three-piece golf ball constructions, golf ballsof the present invention may comprise from 0 to at least 5 intermediatelayer(s), preferably from 0 to 3 intermediate layer(s), more preferablyfrom 1 to 3 intermediate layer(s), and most preferably 1 to 2intermediate layer(s).

The present invention can be used to form golf balls of any desiredsize. “The Rules of Golf” by the USGA dictate that the size of acompetition golf ball must be at least 1.680 inches in diameter;however, golf balls of any size can be used for leisure golf play. Thepreferred diameter of the golf balls is from about 1.670 inches to about1.800 inches. Oversize golf balls with diameters above about 1.760inches to as big as 2.75 inches also are within the scope of theinvention.

A. Core

Ball cores of the present invention have a diameter of from about 0.5 toabout 1.62 inches, preferably from about 0.7 to about 1.60 inches, morepreferably from about 1 to about 1.58 inches, yet more preferably fromabout 1.20 to about 1.54 inches, and most preferably from about 1.40 toabout 1.52 inches.

In another preferred embodiment, the golf ball core has at least onecore layer on the center core, the layer having a thickness of fromabout 0.01 inch to about 1.14 inches, preferably from about 0.02 inch toabout 1.12 inches, more preferably from about 0.03 inch to about 1.10inches and most preferably from about 0.04 inch to about 1 inch.

In still another embodiment, two-piece balls are disclosed comprising acore and a cover having a thickness of from about 0.01 to about 0.20inch, preferably from about 0.02 to about 0.15 inch, more preferablyfrom about 0.03 to about 0.10 inch and most preferably from about 0.03to about 0.07 inch. The cover typically has a hardness greater thanabout 25, preferably greater than about 30, and typically greater thanabout 40 Shore D. The ball typically has a PGA ball compression greaterthan about 40, preferably greater than 50, more preferably greater thanabout 60, most preferably greater than about 70.

The golf ball cores of the present invention typically have a PGAcompression of from about 30 to about 190, preferably from about 40 toabout 160, typically from about 50 to about 130, and most preferablyfrom about 60 to about 100.

The Shore D hardness of the core center and core layers made accordingto the present invention may vary from about 10 to about 90, typicallyfrom about 20 to about 80, and even more typically from about 30 toabout 70.

B. Intermediate Layer(s) and Cover Layer

In one preferred embodiment, the golf ball of the present invention is amulti-piece ball having at least one layer comprising a polymer-peptizercomposition as disclosed herein.

In another preferred embodiment, the golf ball of the present inventionis a three-piece ball having a core and/or at least one layer comprisinga polymer-peptizer composition as disclosed herein.

In yet another preferred embodiment of the present invention, the golfball of the present invention is a four-piece ball having a core and/orat least one layer comprising a polymer-peptizer composition asdisclosed herein.

The one or more intermediate layers of the golf balls of the presentinvention has a thickness of from about 0.01 to about 0.20 inch,preferably from about 0.02 to about 0.15 inch, more preferably fromabout 0.03 to about 0.10 inch and most preferably from about 0.03 toabout 0.06 inch.

The one or more intermediate layers of the golf balls of the presentinvention also has a Shore D hardness greater than about 25, preferablygreater than about 30, and typically greater than about 40.

The one or more intermediate layers of the golf balls of the presentinvention also has a flexural modulus from about 5 to about 500 kpsi,preferably from about 15 to about 300 kpsi, more preferably from about20 to about 200 kpsi, and most preferably from about 25 to about 100kpsi.

The cover layer of the balls of the present invention has a thickness offrom about 0.01 to about 0.10 inch, preferably from about 0.02 to about0.08 inch, more preferably from about 0.03 to about 0.07 inch.

The cover layer of the balls of the present invention has a Shore Dhardness of from about 30 to about 75, preferably from about 30 to about70, more preferably from about 45 to about 65.

The coefficient of restitution (COR) is an important physical attributeof golf balls. The coefficient of restitution is the ratio of therelative velocity between two objects after direct impact to therelative velocity before impact. As a result, the COR can vary from 0 to1, with 1 being a perfectly or completely elastic collision and 0 beinga perfectly or completely inelastic collision. Since the COR directlyinfluences the ball's initial velocity after club collision and traveldistance, golf ball manufacturers are interested in this characteristicfor designing and testing golf balls.

One conventional technique for measuring COR uses a golf ball or golfball subassembly, air cannon, and a stationary steel plate. The steelplate provides an impact surface weighing about 100 pounds or about 45kilograms. A pair of ballistic light screens, which measure ballvelocity, are spaced apart and located between the air cannon and thesteel plate. The ball is fired from the air cannon toward the steelplate over a range of test velocities from 50 ft/sec to 180 ft/sec. Asthe ball travels toward the steel plate, it activates each light screenso that the time at each light screen is measured. This provides anincoming time period proportional to the ball's incoming velocity. Theball impacts the steel plate and rebounds through the light screens,which again measure the time period required to transit between thelight screens. This provides an outgoing transit time periodproportional to the ball's outgoing velocity. The coefficient ofrestitution can be calculated by the ratio of the outgoing transit timeperiod to the incoming transit time period, COR=T_(Out)/T_(in).

Another COR measuring method uses a titanium disk. The titanium disk,intending to simulate a golf club, is circular, has a diameter of about4 inches, and has a mass of about 200 grams. The impact face of thetitanium disk also may be flexible and has its own coefficient ofrestitution, as discussed further below. The disk is mounted on an X-Y-Ztable so that its position can be adjusted relative to the launchingdevice prior to testing. A pair of ballistic light screens are spacedapart and located between the launching device and the titanium disk.The ball is fired from the launching device toward the titanium disk ata predetermined test velocity. As the ball travels toward the titaniumdisk, it activates each light screen, so that the time period to transitbetween the light screens is measured. This provides an incoming transittime period proportional to the ball's incoming velocity. The ballimpacts the titanium disk, and rebounds through the light screens whichmeasure the time period to transit between the light screens. Thisprovides an outgoing transit time period proportional to the ball'soutgoing velocity. The COR can be calculated from the ratio of theoutgoing time period to the incoming time period along with the mass ofthe disk (Me) and ball (Mb): COR=(Tout/Tin)×(Me+Mb)+MbMe.

The COR depends on the golf ball construction as well as the chemicalcomposition of the various layers. Peptizers are added to polymericcompositions, particularly compositions comprising unsaturated polymers,to desirably affect one or more physical properties of such compositionswhile substantially maintaining COR values. For example, compositionsmade without using a peptizer had COR values of 0.787, 0.809 and 0.803,whereas the COR value for the same composition made using2,3,5,6-tetrachloropyridinethiol remained essentially constant with CORvalues of 0.791, 0.813 and 0.806, respectively, and at the same time thecore compression decreased. This was unexpected as the general trend inthat typically COR decreases with decreasing core compression). Thus useof the peptizers of the present invention provides the ability tomaintain COR to maximize golf ball performance while allowing foradditional adjustments in ball layer material properties.

III. Polymer-Peptizer Compositions

Certain disclosed embodiments of the present invention concerncompositions comprising a polymer or polymer precursor, particularly anunsaturated polymer or unsaturated polymer precursor (polymer andpolymer precursor are collectively referred to herein as polymer, unlesscontext indicates otherwise), and an effective amount of a peptizercomprising a heteroaryl compound, a heterocycle other than morpholine,an organic sulfur compound comprising at least one heteroatom conjugatedto a functional group bearing a sulfur atom, and combinations thereof.Alternatively, a first composition comprising a polymer or polymerprecursor, particularly an unsaturated polymer or polymer precursor, andan effective amount of one or more peptizers comprising a heteroarylcompound, a heterocycle other than morpholine, an organic sulfurcompound comprising at least one heteroatom conjugated to a functionalgroup bearing a sulfur atom, and combinations thereof, can be combinedwith at least one additional polymer or polymer precursor to form asecond composition that is useful for making a golf ball layer.Disclosed polymer and/or polymer precursor/peptizer compositions alsocan be combined with one or more additional materials, now known orhereafter developed, useful for making golf balls. A partial list ofsuch material includes, without limitation, cross-linking agents, suchas sulfur compounds, peroxides, azides, maleimides, e-beam radiation,gamma-radiation; co-cross-linking agent or agents, such as an agentcomprising zinc or magnesium salts of an unsaturated fatty acid havingfrom about 3 to about 8 carbon atoms; a base resin; an accelerator; a UVstabilizer; a photostabilizer; a photoinitiator; a co-initiator; anantioxidant; a colorant; a dispersant; a mold release agent; aprocessing aid; a fiber; a filler, such as a density adjusting filler, ananofiller, an inorganic filler, and an organic filler; and any and allcombinations thereof. The peptizers are used in amounts effective toachieve a desired result. While this amount can vary, “effective amount”typically refers to an amount greater than 0 part to about 10 parts,more typically from about 0.1 part to about 5 parts, by weight ofpeptizer per 100 parts by weight of the polymer.

Disclosed compositions also often include a cross-linking agent. Theamount of the cross linking agent used also can vary, but typically isan amount of greater than 0 to less than about 5 part, more typicallyless than about 4 part, and most typically less than about 3 part, byweight of the cross-linking agent per 100 parts by weight of thepolymer.

A. Unsaturated Polymers

Any processable polymeric material, or mixture of polymeric materials,that is useful for forming a golf ball core or layer that is now knownor hereafter developed, and which can be advantageously modified by theaddition of an effective amount of a peptizer comprising a heteroarylcompound, a heterocycle other than morpholine, an organic sulfurcompound comprising at least one heteroatom conjugated to a functionalgroup bearing a sulfur atom, and combinations thereof, can be used toform useful compositions of the present invention. Typically theprocessable polymeric material or mixture of polymeric materialscomprises an unsaturated polymer or polymer precursor. Unsaturatedpolymers suitable for use in the golf balls of the present inventioninclude any polymeric material having unsaturation, either hydrocarbonor non-hydrocarbon, capable of participating in a cross-linking reactioninitiated by some means, such as thermally, chemically, by irradiation,or by a combination of these methods. Non-limiting examples of suitableclasses of unsaturated polymers include synthetic and natural rubbers,polyalkenamers, olefinic thermoplastic elastomers, and combinationsthereof. Particular examples of such polymers (or polymer precursorsused to make such polymers) include, without limitation,1,2-polybutadiene, cis-1,4-polybutadiene, trans-1,4-polybutadiene,cis-polyisoprene, trans-polyisoprene, polychloroprene, polybutylene,styrene-butadiene rubber, styrene-butadiene-styrene block copolymer,styrene-isoprene-styrene block copolymer, nitrile rubber, siliconerubber, and polyurethane, as well as mixtures of these. These and otherexemplary unsaturated polymers are discussed further below.

1. Synthetic and Natural Rubbers

Traditional rubber components used in golf ball applications can be usedto make golf balls according to the present invention including, withoutlimitation, both natural and synthetic rubbers, such ascis-1,4-polybutadienes, trans-1,4-polybutadienes, 1,2-polybutadienes,cis-polyisoprenes, trans-polyisoprenes, polychloroprenes, polybutylenes,styrene-butadiene rubbers, styrene-butadiene-styrene block copolymersand partially and fully hydrogenated equivalents,styrene-isoprene-styrene block copolymers and partially and fullyhydrogenated equivalents, nitrile rubbers, silicone rubbers, andpolyurethanes, as well as mixtures of these materials. Polybutadienerubbers, especially 1,4-polybutadiene rubbers containing at least 40 mol%, and more preferably 80 to 100 mol % of cis-1,4 bonds, are preferredbecause of their high rebound resilience, moldability, and high strengthafter vulcanization. The polybutadiene component may be purchased, ifcommercially available, or synthesized by methods now known or hereafterdeveloped, including using rare earth-based catalysts, nickel-basedcatalysts, or cobalt-based catalysts, that conventionally are used inthis field. Polybutadiene obtained by using lanthanum rare earth-basedcatalysts usually employ a combination of a lanthanum rare earth (atomicnumber of 57 to 71) compound, but particularly preferred is a neodymiumcompound.

The 1,4-polybutadiene rubbers have a molecular weight distribution(Mw/Mn) of from about 1.2 to about 4.0, preferably from about 1.7 toabout 3.7, even more preferably from about 2.0 to about 3.5, and mostpreferably from about 2.2 to about 3.2. The polybutadiene rubbers have aMooney viscosity (ML₁₊₄ (100° C.)) of from about −10 to about 80,preferably from about 20 to about 70, even more preferably from about 30to about 60, and most preferably from about 35 to about 50. “Mooneyviscosity” refers to an industrial index of viscosity as measured with aMooney viscometer, which is a type of rotary plastometer (see JISK6300). This value is represented by the symbol ML₁₊₄ (100° C.), wherein“M” stands for Mooney viscosity, “L” stands for large rotor (L-type),“1+4” stands for a pre-heating time of 1 minute and a rotor rotationtime of 4 minutes, and “100° C.” indicates that measurement was carriedout at a temperature of 100° C.

Examples of 1,2-polybutadienes having differing tacticity, all of whichare suitable as unsaturated polymers for use in the present invention,are atactic 1,2-polybutadienes, isotactic 1,2-polybutadienes, andsyndiotactic 1,2-polybutadienes. Syndiotactic 1,2-polybutadienes(syndiotactic polymers include alternating base units that areenantiomers of each other) having crystallinity suitable for use as anunsaturated polymer in compositions within the scope of the presentinvention are polymerized from a 1,2-addition of butadiene. Golf ballswithin the scope of the present invention include syndiotactic1,2-polybutadienes having crystallinity and greater than about 70% of1,2-bonds, more preferably greater than about 80% of 1,2-bonds, and mostpreferably greater than about 90% of 1,2-bonds. Also, golf balls withinthe scope of the present invention not only have such crystallinity butalso have a mean molecular weight of between from about 10,000 to about350,000, more preferably between from about 50,000 to about 300,000,more preferably between from about 80,000 to about 200,000, and mostpreferably between from about 10,000 to about 150,000. Examples ofsuitable syndiotactic 1,2-polybutadienes having crystallinity suitablefor use in golf balls within the scope of the present invention are soldunder the trade names RB810, RB820, and RB830 by JSR Corporation ofTokyo, Japan. These have more than 90% of 1,2 bonds, a mean molecularweight of approximately 120,000, and crystallinity between about 15% andabout 30%.

As with all disclosed components, the poly(1,4-butadiene) rubbers can beblended with other materials as desired. For example, thepoly(1,4-butadiene) rubbers can be blended with natural rubber,polyisoprene rubber, styrene-butadiene rubber, or the like.

2. Polyalkenamers

Examples of suitable polyalkenamer rubbers are polypentenamer rubber,polyheptenamer rubber, polyoctenamer rubber, polydecenamer rubber andpolydodecenamer rubber. For further details concerning polyalkenamerrubber, see Rubber Chem. & Tech., Vol. 47, page 511-596, 1974, which isincorporated herein by reference. Polyoctenamer rubbers are commerciallyavailable from Degussa AG of Dusseldorf, Germany, and sold under thetrademark VESTENAMER®. Two grades of the VESTENAMER® trans-polyoctenamerare commercially available: VESTENAMER 8012 designates a material havinga trans-content of approximately 80% (and a cis-content of 20%) with amelting point of approximately 54° C.; and VESTENAMER 6213 designates amaterial having a trans-content of approximately 60% (cis-content of40%) with a melting point of approximately 30° C. Both of these polymershave a double bond at every eighth carbon atom in the ring.

The polyalkenamer rubber preferably contains from about 50 to about 99,preferably from about 60 to about 99, more preferably from about 65 toabout 99, even more preferably from about 70 to about 90 percent of itsdouble bonds in the trans-configuration. The preferred form of thepolyalkenamer for use in the practice of the invention has a transcontent of approximately 80%; however, compounds having other ratios ofthe cis- and trans-isomeric forms of the polyalkenamer also can beobtained by blending available products for use in the invention.

The polyalkenamer rubber has a molecular weight (as measured by GPC)from about 10,000 to about 300,000, preferably from about 20,000 toabout 250,000, more preferably from about 30,000 to about 200,000, evenmore preferably from about 50,000 to about 150,000.

The polyalkenamer rubber has a degree of crystallization (as measured byDSC secondary fusion) from about 5% to about 70%, preferably from about6% to about 50%, more preferably from about from 6.5% to about 50%, evenmore preferably from about from 7% to about 45%.

More preferably, the polyalkenamer rubber used in the present inventionis a polymer prepared by polymerization of cyclooctene to form atrans-polyoctenamer rubber as a mixture of linear and cyclicmacromolecules.

3. Olefinic Thermoplastic Elastomers

Examples of olefinic thermoplastic elastomers include, withoutlimitation, metallocene-catalyzed polyolefins, ethylene-octenecopolymers, ethylene-butene copolymers, and ethylene-propylenecopolymers all with or without controlled tacticity as well as blends ofpolyolefins having ethyl-propylene-non-conjugated diene terpolymers,rubber-based copolymers, and dynamically vulcanized rubber-basedcopolymers. Examples of such polymers that are commercially availableinclude products sold under the trade names SANTOPRENE, DYTRON,VISTAFLEX, and VYRAM by Advanced Elastomeric Systems of Houston, Tex.,and SARLINK by DSM of Haarlen, the Netherlands.

A preferred group of polymers for making the presently disclosedcompositions includes polybutadienes, polyisoprenes, butadienecopolymers, isoprene copolymers, polyalkenamers, and mixtures thereof.

B. Peptizers

Peptizers of the present invention typically are aromatic or conjugatedpeptizers comprising one or more heteroatoms, such as nitrogen, oxygenand/or sulfur. More typically, peptizers of the present invention areheteroaryl or heterocyclic compounds (other than the morpholine-typepeptizers represented by 4,4′ dithio-dimorpholine, as disclosed in U.S.application Ser. Nos. 10/662,619, 10/662,626, 10/662,628 and 10/662,719,entitled “Golf Balls Incorporating Peptizers and Method of Manufacture,”which are incorporated herein by reference) having at least oneheteroatom, and potentially plural heteroatoms, where the pluralheteroatoms may be the same or different. Suitable peptizers also mayinclude one or more additional functional groups, such as halogens,particularly chlorine; a sulfur-containing moiety exemplified by thiols,where the functional group is sulfhydryl (—SH), thioethers, where thefunctional group is —SR, disulfides, (R₁S—SR₂), etc.; and combinationsof functional groups. A person of ordinary skill in the art also willappreciate that combinations of such peptizers also might be used tomake disclosed compositions.

A first general structural formula depicting disclosed heteroaryl orheterocyclic peptizer embodiments is provided by Formula 1. Formula 1concerns cyclic peptizers having at least one heteroatom, A, typicallynitrogen, oxygen, or sulfur, and most typically nitrogen, in an aromaticor conjugated system, as indicated by the dashed inner circle. Theheteroaryl or heterocyclic peptizers of the present invention caninclude plural heteroatoms, indicated as (A)_(m), where m is from 1 ton, where n is the number of atoms in the ring. Formula 1 indicates thatat least one additional second ring, and perhaps plural such additionalrings, either fused or otherwise linked to a first ring, is optionallypresent, as indicated by the dashed circle in Formula 1. R optionally ispresent, depending on the heteroatom and whether it can include an Rgroup. If present, R typically is hydrogen or an aliphatic group.

Structural chemical formulas provided herein may not depict all bondsfor all atoms represented by such formulas. Additional atoms orfunctional groups may be bonded to atoms that do not have a fullcomplement of bonds depicted to form suitable peptizer compounds. Theseatoms or groups typically are independently hydrogen, halogen, oraliphatic groups, particularly alkyl groups.

Heteroaryl or heterocyclic peptizers of the present invention include aring having from about 3 atoms to at least about 10 ring atoms, moretypically from about 4 to about 7 ring atoms, and most typically fromabout 5 to about 6 ring atoms. Disclosed heteroaryl or heterocyclicpeptizers can have linked or fused rings; each of the plural rings mayhave the same number of atoms per ring or a different number of atomsper ring; and one or more of the rings can include one or moreheteroatoms, e.g. nitrogen. Compounds comprising nitrogen may have theone or more nitrogen atoms double bonded within the ring, such as to acarbon atom or to another nitrogen atom. Alternatively, the nitrogenatom may include a substituent, the optional presence thereof beingindicated by a dashed bond to an R group substituent, which typically ishydrogen or an aliphatic group, typically an alkyl group having 10 orfewer carbon atoms.

A person of ordinary skill in the art will appreciate that disclosedpeptizers need not by cyclic, nor aromatic. Acyclic conjugated systemscomprising a heteroatom also can function appropriately as peptizers.These conjugated systems also may include a sulfur moiety, such as athiol or disulfide, and if so satisfy Formula 2 or Formula 3.

With reference to Formulas 2 and 3, A is a heteroatom, typicallynitrogen, oxygen, or sulfur, and most typically nitrogen. R₁ generallyis hydrogen or an aliphatic group, more typically alkyl, alkenyl oralkynyl groups having 10 or fewer carbon atoms. Disclosed peptizerembodiments typically include at least one sulfur moiety, indicated as—SR₂. R₂ independently is hydrogen, sulfur (e.g., —S—S—R₃ where R₃ ishydrogen, an aliphatic group, or defines a cyclic organic compound) oran aliphatic group, more typically an alkyl, alkenyl or alkynyl grouphaving 10 or fewer carbon atoms, with exemplary functional groupsincluding, for example, sulfhydryl, thioethers, disulfides, etc. R₁ andR₂ also can be bonded to other atoms along the chain, or to each other,to form a cyclic, conjugated system.

Formula 2 indicates that disclosed peptizers include at least one siteof unsaturation, which is exemplified by the double bond depicted byFormula 2. Formula 3 indicates that the compounds can have at least twosites of unsaturation. A person of ordinary skill in the art willappreciate that suitable peptizers may have more than two sites ofunsaturation. Moreover, the site of unsaturation can be a carbon-carbondouble bond or a carbon-carbon triple bond. The site of unsaturationalso may include an atom other than carbon, such as oxygen or sulfur ina carbonyl (—C═O, —C═S) or nitrogen in an imine (—N═C—). The functionalgroup also can exist as a tautomer. For example, with reference toFormulas 2 and 3, compounds having A=oxygen and R₁=to hydrogen define anenol that may tautomerize to the keto form.

Heteroaryl or heterocyclic peptizers of the present invention alsotypically satisfy Formula 4

where A is a heteroatom, typically nitrogen, oxygen, or sulfur, and mosttypically nitrogen. The heteroaryl or heterocyclic peptizers of thepresent invention can include plural heteroatoms, indicated as (A)_(m),where m is from 1 to n, where n is the number of atoms in the ring.R₁-R₂ are the same or different, and are independently hydrogen, sulfur(e.g., —S—S—R₄ where R₄ is hydrogen, an aliphatic group, or defines acyclic organic compound) and aliphatic groups. The relative location ofthe sulfur moiety to the at least one heteroatom in the ring or in aconjugated system, as well as the relationship of any two moieties on aring or in a conjugated system, can vary, e.g. from a 1-2, 1-3, 1-4,etc. relationship. R₃ optionally is present, depending on the heteroatomand whether it can include an R₃ group, but if present R₃ typically ishydrogen or an aliphatic group.

Disclosed heteroaryl or heterocyclic peptizers also may be substituted,and these compounds generally satisfy the following Formula 5.

With reference to Formula 5, A is a heteroatom, typically nitrogen,oxygen, or sulfur, and most typically nitrogen. The heteroaryl orheterocyclic peptizers of the present invention can include pluralheteroatoms, indicated as (A)_(m), where m is from 1 to n, where n isthe number of atoms in the ring. R₁-R₂ are the same or different, andare independently hydrogen, sulfur (e.g., —S—S—R₄ where R₄ is hydrogen,an aliphatic group, or defines a cyclic organic compound) and aliphaticgroups. R₃ is optionally present, depending on the heteroatom andwhether it can include an R₃ group. If present, R₃ typically is hydrogenor an aliphatic group. R₄ and R₅ are the same or different, andtypically are independently hydrogen, halogen, and aliphatic groups,particularly alkyl groups.

A preferred class of peptizers according to the present invention is the6-membered ring, nitrogen-based heteroaryl compounds illustrated bygeneral structural Formula 6.

With reference to Formula 6, V-Z may be the same or different, and areindependently carbon and heteroatoms, including without limitation,nitrogen, oxygen and sulfur, and preferably are independently carbon andnitrogen. One or more rings positions may include a substituent R,represented as being present in the alternative by the dashed bond, andbeing positionably variable as represented by the dashed bond beingdrawn to a ring bond and not an atom. R typically is halogen,sulfur-bearing moieties, such as sulfhydryl or disulfide, aliphaticgroups, typically lower alkyl groups, and combinations thereof. Thenumber of R groups also can vary as indicated by “n,” where n can varyfrom 1-5. If a ring atom does not include an R group, then it may bebonded to a hydrogen atom, as would be understood by a person ofordinary skill in the art.

Formula 7 is a more specific, but still general, structural chemicalformula depicting suitable 6-membered ring, nitrogen-based heteroarylpeptizers of the present invention.

As with Formula 6, V-Z of Formula 7 may be the same or different, andare independently carbon and heteroatoms, including without limitation,nitrogen, oxygen and sulfur, and preferably are independently carbon andnitrogen. R₁-R₅ typically are hydrogen, halogen, sulfur-bearingmoieties, such as sulfhydryl or disulfide, aliphatic groups, typicallylower alkyl groups, and combinations thereof.

Exemplary nitrogen-based, heteroaryl compounds include pyridine-basedcompounds, exemplified by Formula 8; diazine compounds, such aspyrimidine- and pyradazine-based compounds, exemplified by Formulas9-11; and triazine-based compounds, exemplified by Formula 12. Again,with reference to Formulas 8-12, R₁-R₅ typically are hydrogen, halogen,sulfur-bearing moieties, such as sulfhydryl or disulfide, aliphaticgroups, typically lower alkyl groups, and combinations thereof.

With reference to Formulas 8-12, R₁-R₅ may be the same or different andtypically are independently hydrogen, lower aliphatic, typically loweralkyl, most typically C1 to C8 alkyl groups, halogen, particularlychlorine, sulfur-containing moieties, particularly sulfhydryl ordisulfide, and may be other functional groups, such as carbonyl,carboxyl and/or sulfonate.

Working embodiments typically have used halogenated, pyridine-basedthiol peptizers. These peptizers are exemplified by2,3,5,6-tetrachloro-4-pyridinethiol, shown below.

2,3,5,6-tetrachloro-4-pyridinethiol

Peptizers of the present invention can be used alone, in combination,and in combination with other known peptizers, such as an organic,sulfur-bearing compound and/or its metal or non-metal salt. Examples,without limitation, of organic, sulfur-bearing peptizer compoundsinclude thiophenols, such as pentachlorothiophenol,4-butyl-o-thiocresol, 4 t-butyl-p-thiocresol, 2-benzamidothiophenol,thiocarboxylic acids, such as thiobenzoic acid, 4,4′dithio-dimorpholine, sulfides, such as dixylyl disulfide, dibenzoyldisulfide, dibenzothiazyl disulfide, di(pentachlorophenyl)disulfide,dibenzamido diphenyldisulfide (DBDD), and alkylated phenol sulfides,such as VULTAC marketed by Atofina Chemicals, Inc. of Philadelphia, Pa.

Compounds represented by Formulas 1-12, as well as known peptizers, alsocan be used as salts. Any suitable salt can be used, including metalsalts of such compounds, non-metal salts of such compounds, and mixedmetal and non-metal salts of such compounds. Specific examples of metalsuseful for forming metal salts of disclosed and known peptizers include,without limitation, sodium, potassium, lithium, magnesium, calcium,barium, cesium and zinc salts, with zinc salts currently beingpreferred. Examples of non-metal salts of disclosed and known peptizersinclude, without limitation, ammonium salts, where the ammonium cationhas the general formula [NR₁R₂R₃R₄]⁺ where R₁, R₂, R₃ and R₄ arehydrogen, a C₁-C₂₀ aliphatic, cycloaliphatic or aromatic moiety, and anyand all combinations thereof, with the preferred ammonium cation beingNH⁴⁺.

The peptizer, if employed to manufacture golf balls of the presentinvention, is present in an amount effective to achieve the desiredresult, which effective amount typically is from about 0.01 part toabout 10 parts by weight, preferably from about 0.10 part to about 7parts by weight, more preferably from about 0.15 part to about 5 partsby weight per 100 parts by weight of the polymer component.

C. Cross-Linking Agents

Any crosslinking or curing system typically used for rubber crosslinkingmay be used to crosslink the disclosed polymer and/or polymerprecursor/peptizer compositions of the present invention. Satisfactorycrosslinking systems are based on sulfur-, peroxide-, azide-, maleimide-or resin-vulcanization agents, which may be used in conjunction with avulcanization accelerator. Examples of satisfactory crosslinking systemcomponents are zinc oxide, sulfur, organic peroxide, azo compounds,magnesium oxide, benzothiazole sulfenamide accelerator, benzothiazyldisulfide, phenolic curing resin, m-phenylene bis-maleimide, thiuramdisulfide and dipentamethylene-thiuram hexasulfide.

More preferable cross-linking agents include peroxides, sulfurcompounds, as well as mixtures of these. Non-limiting examples ofsuitable cross-linking agents include primary, secondary, or tertiaryaliphatic or aromatic organic peroxides. Peroxides containing more thanone peroxy group can be used, such as2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 1,4-di-(2-tert-butylperoxyisopropyl)benzene. Both symmetrical and asymmetrical peroxides canbe used including, for example, tert-butyl perbenzoate and tert-butylcumyl peroxide. Peroxides incorporating carboxyl groups also aresuitable. The decomposition of peroxides used as cross-linking agents inthe present invention can be brought about by applying thermal energy,shear, irradiation, reaction with other chemicals, or any combination ofthese. Both homolytically and heterolytically decomposed peroxide can beused in the present invention. Non-limiting examples of suitableperoxides include: diacetyl peroxide; di-tert-butyl peroxide; dibenzoylperoxide; dicumyl peroxide; 2,5-dimethyl-2,5-di(benzoylperoxy)hexane;1,4-bis-(t-butylperoxyisopropyl)benzene; t-butylperoxybenzoate;2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3, such as Trigonox 145-45B,marketed by Akzo Nobel Polymer Chemicals of Chicago, Ill.;1,1-bis(t-butylperoxy)-3,3,5 tri-methylcyclohexane, such as Varox231-XL, marketed by R.T. Vanderbilt Co., Inc., of Norwalk, Conn.; anddi-(2,4-dichlorobenzoyl)peroxide.

The cross-linking agents are blended with the polymeric material ineffective amounts, which typically vary in total amounts of from about0.05 part to about 5 parts, more preferably from about 0.2 part to about3 parts, and most preferably from about 0.2 part to about 2 parts, byweight of the cross-linking agents per 100 parts by weight of thedisclosed polymer and/or polymer precursor/peptizer compositions in thepresent invention

Each peroxide cross-linking agent has a characteristic decompositiontemperature at which 50% of the cross-linking agent has decomposed whensubjected to that temperature for a specified time period (t_(1/2)). Forexample, 1,1-bis-(t-butylperoxy)-3,3,5-tri-methylcyclohexane att_(1/2)=0.1 hr has a decomposition temperature of 138° C. and2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3 at t_(1/2)=0.1 hr has adecomposition temperature of 182° C. Two or more cross-linking agentshaving different characteristic decomposition temperatures at the samet_(1/2) may be blended in the composition. For example, where at leastone cross-linking agent has a first characteristic decompositiontemperature less than 150° C., and at least one cross-linking agent hasa second characteristic decomposition temperature greater than 150° C.,the composition weight ratio of the at least one cross-linking agenthaving the first characteristic decomposition temperature to the atleast one cross-linking agent having the second characteristicdecomposition temperature can range from 5:95 to 95:5, or morepreferably from 10:90 to 50:50.

Besides the use of chemical cross-linking agents, exposure of thedisclosed polymer and/or polymer precursor/peptizer compositions in thepresent invention to radiation also can serve as a cross-linking agent.Radiation can be applied to the disclosed polymer and/or polymerprecursor/peptizer compositions by any known method, including usingmicrowave, UV, electron-beam, or gamma radiation. Additives may also beused to improve radiation-induced crosslinking of the disclosed polymerand/or polymer precursor/peptizer compositions in the present invention

D. Co-Cross-Linking Agent

The disclosed polymer and/or polymer precursor/peptizer compositions inthe present invention may also be blended with a co-cross-linking agent.For example, the co-cross linking agent which may be a metal salt of anunsaturated carboxylic acid. Examples of these include zinc andmagnesium salts of unsaturated fatty acids having from about 3 to about8 carbon atoms, such as acrylic acid, methacrylic acid, maleic acid,fumaric acid and palmitic acid, with the zinc salts of acrylic andmethacrylic acid being preferred, and with zinc diacrylate being mostpreferred. The unsaturated carboxylic acid metal salt can be blended inthe disclosed polymer and/or polymer precursor/peptizer compositionseither as a preformed metal salt, or by introducing an α,β-unsaturatedcarboxylic acid and a metal oxide or hydroxide into the disclosedpolymer and/or polymer precursor/peptizer compositions, and allowingthem to react to form the metal salt. The unsaturated carboxylic acidmetal salt can be blended in any desired amount, but preferably inamounts of from about 10 parts to about 100 parts by weight of theunsaturated carboxylic acid per 100 parts by weight of the disclosedpolymer and/or polymer precursor/peptizer compositions in the presentinvention

E. Accelerators

The disclosed polymer and/or polymer precursor/peptizer compositions ofthe present invention also can comprise one or more accelerators of oneor more classes. Accelerators are added to an unsaturated polymer toincrease the vulcanization rate and/or decrease the vulcanizationtemperature. Accelerators can be of any class known for rubberprocessing including mercapto-, sulfenamide-, thiuram, dithiocarbamate,dithiocarbamyl-sulfenamide, xanthate, guanidine, amine, thiourea, anddithiophosphate accelerators. Specific commercial accelerators include2-mercaptobenzothiazole and its metal or non-metal salts, such asVulkacit Mercapto C, Mercapto MGC, Mercapto ZM-5, and ZM marketed byBayer AG of Leverkusen, Germany, Nocceler M, Nocceler M Z, and NoccelerM-60 marketed by Ouchisinko Chemical Industrial Company, Ltd. of Tokyo,Japan, and MBT and ZMBT marketed by Akrochem Corporation of Akron, Ohio.A more complete list of commercially available accelerators is given inThe Vanderbilt Rubber Handbook: 13^(th) Edition (1990, R.T. VanderbiltCo.), pp. 296-330, in Encyclopedia of Polymer Science and Technology,Vol. 12 (1970, John Wiley & Sons), pp. 258-259, and in Rubber TechnologyHandbook (1980, Hanser/Gardner Publications), pp. 234-236. Preferredaccelerators include 2-mercaptobenzothiazole (MBT) and its salts.

The disclosed polymer and/or polymer precursor/peptizer compositions canfurther incorporate from about 0.1 part to about 10 parts by weight ofthe accelerator per 100 parts by weight of the disclosed polymer and/orpolymer precursor/peptizer compositions. More preferably, the ballcomposition can further incorporate from about 0.2 part to about 5parts, and most preferably from about 0.5 part to about 1.5 parts, byweight of the accelerator per 100 parts by weight of the disclosedpolymer and/or polymer precursor/peptizer compositions.

IV. Additional Polymeric Materials

The following polymeric materials are provided solely as examples ofmaterials useful for forming golf ball cores, intermediate layers,and/or cover layers. These materials can be used in combination with thedisclosed peptizers if such compositions provide a desired composition.Alternatively, the following polymeric materials can be used incombination with a first polymer composition that includes a peptizer.As yet another alternative, the following polymeric materials may beused to make one or more golf ball layers that does not include thedisclosed peptizers, but where at least one ball layer does include atleast one disclosed peptizer. A person of ordinary skill in the art willrecognize that the present invention is not limited solely to thosematerials listed herein by way of example. Moreover, a person ofordinary skill in the art also will recognize that various combinationsof such materials can be used to form the core, intermediate layer(s)and/or outer cover layer.

Additional guidance for selecting materials useful for making golf ballsaccording to the disclosed embodiments is provided by considering thosephysical properties desirable for making golf balls. In addition to theexemplary list of materials provided herein, a person of ordinary skillin the art might consider compression, hardness, density, flexuralmodulus, elasticity, COR, impact durability, tensile properties, meltflow index, acoustic behavior, compatibility, processability, etc., inview of values stated herein for such properties, values that aretypical in the field, or values that otherwise would be known to aperson of ordinary skill in the field.

A. General Description of Polymeric Materials

Polymeric materials generally considered useful for making golf ballsaccording to the process of the present invention include, withoutlimitation, synthetic and natural rubbers, thermoset polymers such asthermoset polyurethanes and thermoset polyureas, as well asthermoplastic polymers including thermoplastic elastomers such asmetallocene catalyzed polymer, unimodal ethylene/carboxylic acidcopolymers, unimodal ethylene/carboxylic acid/carboxylate terpolymers,bimodal ethylene/carboxylic acid copolymers, bimodal ethylene/carboxylicacid/carboxylate terpolymers, unimodal ionomers, bimodal ionomers,modified unimodal ionomers, modified bimodal ionomers, thermoplasticpolyurethanes, thermoplastic polyureas, polyamides, copolyamides,polyesters, copolyesters, polycarbonates, polyolefins, halogenated (e.g.chlorinated) polyolefins, halogenated polyalkylene compounds, such ashalogenated polyethylene [e.g. chlorinated polyethylene (CPE)],polyalkenamer, polyphenylene oxides, polyphenylene sulfides, diallylphthalate polymers, polyimides, polyvinyl chlorides, polyamide-ionomers,polyurethane-ionomers, polyvinyl alcohols, polyarylates, polyacrylates,polyphenylene ethers, impact-modified polyphenylene ethers,polystyrenes, high impact polystyrenes, acrylonitrile-butadiene-styrenecopolymers, styrene-acrylonitriles (SAN),acrylonitrile-styrene-acrylonitriles, styrene-maleic anhydride (S/MA)polymers, styrenic copolymers, functionalized styrenic copolymers,functionalized styrenic terpolymers, styrenic terpolymers, cellulosicpolymers, liquid crystal polymers (LCP), ethylene-propylene-dieneterpolymers (EPDM), ethylene-vinyl acetate copolymers (EVA),ethylene-propylene copolymers, ethylene vinyl acetates, polyureas, andpolysiloxanes and any and all combinations thereof.

More specific examples of particular polymeric materials useful formaking golf ball cores, optional intermediate layer(s) and outer covers,again without limitation, are provided below.

B. Polyalkenamers

Examples of suitable polyalkenamer rubbers are polypentenamer rubber,polyheptenamer rubber, polyoctenamer rubber, polydecenamer rubber andpolydodecenamer rubber. For further details concerning polyalkenamerrubber, see Rubber Chem. & Tech., Vol. 47, page 511-596, 1974, which isincorporated herein by reference. Polyoctenamer rubbers are commerciallyavailable from Degussa AG of Dusseldorf, Germany, and sold under thetrademark VESTENAMER®. Two grades of the VESTENAMER® trans-polyoctenamerare commercially available: VESTENAMER 8012 designates a material havinga trans-content of approximately 80% (and a cis-content of 20%) with amelting point of approximately 54° C.; and VESTENAMER 6213 designates amaterial having a trans-content of approximately 60% (cis-content of40%) with a melting point of approximately 30° C. Both of these polymershave a double bond at every eighth carbon atom in the ring.

The polyalkenamer rubber preferably contains from about 50 to about 99,preferably from about 60 to about 99, more preferably from about 65 toabout 99, even more preferably from about 70 to about 90 percent of itsdouble bonds in the trans-configuration. The preferred form of thepolyalkenamer for use in the practice of the invention has a transcontent of approximately 80%; however, compounds having other ratios ofthe cis- and trans-isomeric forms of the polyalkenamer also can beobtained by blending available products for use in the invention.

The polyalkenamer rubber has a molecular weight (as measured by GPC)from about 10,000 to about 300,000, preferably from about 20,000 toabout 250,000, more preferably from about 30,000 to about 200,000, evenmore preferably from about 50,000 to about 150,000.

The polyalkenamer rubber has a degree of crystallization (as measured byDSC secondary fusion) from about 5% to about 70%, preferably from about6% to about 50%, more preferably from about from 6.5% to about 50%, evenmore preferably from about from 7% to about 45%.

More preferably, the polyalkenamer rubber used in the present inventionis a polymer prepared by polymerization of cyclooctene to form atrans-polyoctenamer rubber as a mixture of linear and cyclicmacromolecules.

Prior to its use in the golf balls of the present invention, thepolyalkenamer rubber may be further formulated with one or more of thefollowing blend components:

1. Polyalkenamer Cross-Linking Agents

Any crosslinking or curing system typically used for rubber crosslinkingmay be used to crosslink the polyalkenamer rubber used in the presentinvention. Satisfactory crosslinking systems are based on sulfur-,peroxide-, azide-, maleimide- or resin-vulcanization agents, which maybe used in conjunction with a vulcanization accelerator. Examples ofsatisfactory crosslinking system components are zinc oxide, sulfur,organic peroxide, azo compounds, magnesium oxide, benzothiazolesulfenamide accelerator, benzothiazyl disulfide, phenolic curing resin,m-phenylene bis-maleimide, thiuram disulfide anddipentamethylene-thiuram hexasulfide.

More preferable cross-linking agents include peroxides, sulfurcompounds, as well as mixtures of these. Non-limiting examples ofsuitable cross-linking agents include primary, secondary, or tertiaryaliphatic or aromatic organic peroxides. Peroxides containing more thanone peroxy group can be used, such as2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 1,4-di-(2-tert-butylperoxyisopropyl)benzene. Both symmetrical and asymmetrical peroxides canbe used, for example, tert-butyl perbenzoate and tert-butyl cumylperoxide. Peroxides incorporating carboxyl groups also are suitable. Thedecomposition of peroxides used as cross-linking agents in the presentinvention can be brought about by applying thermal energy, shear,irradiation, reaction with other chemicals, or any combination of these.Both homolytically and heterolytically decomposed peroxide can be usedin the present invention. Non-limiting examples of suitable peroxidesinclude: diacetyl peroxide; di-tert-butyl peroxide; dibenzoyl peroxide;dicumyl peroxide; 2,5-dimethyl-2,5-di(benzoylperoxy)hexane;1,4-bis-(t-butylperoxyisopropyl)benzene; t-butylperoxybenzoate;2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3, such as Trigonox 145-45B,marketed by Akzo Nobel Polymer Chemicals of Chicago, Ill.;1,1-bis(t-butylperoxy)-3,3,5 tri-methylcyclohexane, such as Varox231-XL, marketed by R.T. Vanderbilt Co., Inc., of Norwalk, Conn.; anddi-(2,4-dichlorobenzoyl)peroxide.

The cross-linking agents are blended with the polymeric material ineffective amounts, which typically vary in total amounts of from about0.05 part to about 5 parts, more preferably about 0.2 part to about 3parts, and most preferably about 0.2 part to about 2 parts, by weight ofthe cross-linking agents per 100 parts by weight of the polyalkenamerrubber.

Each peroxide cross-linking agent has a characteristic decompositiontemperature at which 50% of the cross-linking agent has decomposed whensubjected to that temperature for a specified time period (t_(1/2)). Forexample, 1,1-bis-(t-butylperoxy)-3,3,5-tri-methylcyclohexane att_(1/2)=0.1 hr has a decomposition temperature of 138° C. and2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3 at t_(1/2)=0.1 hr has adecomposition temperature of 182° C. Two or more cross-linking agentshaving different characteristic decomposition temperatures at the samet_(1/2) may be blended in the composition. For example, where at leastone cross-linking agent has a first characteristic decompositiontemperature less than 150° C., and at least one cross-linking agent hasa second characteristic decomposition temperature greater than 150° C.,the composition weight ratio of the at least one cross-linking agenthaving the first characteristic decomposition temperature to the atleast one cross-linking agent having the second characteristicdecomposition temperature can range from 5:95 to 95:5, or morepreferably from 10:90 to 50:50.

Besides the use of chemical cross-linking agents, exposure of thepolyalkenamer rubber composition to radiation also can serve as across-linking agent. Radiation can be applied to the polyalkenamerrubber mixture by any known method, including using microwave UV,electron-beam, or gamma radiation. Additives may also be used to improveradiation-induced crosslinking of the polyalkenamer rubber.

2. Co-Cross-Linking Agent

The polyalkenamer rubber may also be blended with a co-cross-linkingagent, which may be a metal salt of an unsaturated carboxylic acid.Examples of these include zinc and magnesium salts of unsaturated fattyacids having from about 3 to about 8 carbon atoms, such as acrylic acid,methacrylic acid, maleic acid, fumaric acid and palmitic acid, with thezinc salts of acrylic and methacrylic acid being preferred, and withzinc diacrylate being most preferred. The unsaturated carboxylic acidmetal salt can be blended in the polyalkenamer rubber either as apreformed metal salt, or by introducing an α,β-unsaturated carboxylicacid and a metal oxide or hydroxide into the polyalkenamer rubbercomposition, and allowing them to react to form the metal salt. Theunsaturated carboxylic acid metal salt can be blended in any desiredamount, but preferably in amounts of about 10 parts to about 100 partsby weight of the unsaturated carboxylic acid per 100 parts by weight ofthe polyalkenamer rubber.

3. Accelerators

The polyalkenamer rubber composition also can comprise one or moreaccelerators of one or more classes. Accelerators are added to anunsaturated polymer to increase the vulcanization rate and/or decreasethe vulcanization temperature. Accelerators can be of any class knownfor rubber processing including mercapto-, sulfenamide-, thiuram,dithiocarbamate, dithiocarbamyl-sulfenamide, xanthate, guanidine, amine,thiourea, and dithiophosphate accelerators. Specific commercialaccelerators include 2-mercaptobenzothiazole and its metal or non-metalsalts, such as Vulkacit Mercapto C, Mercapto MGC, Mercapto ZM-5, and ZMmarketed by Bayer AG of Leverkusen, Germany, Nocceler M, Nocceler MZ,and Nocceler M-60 marketed by Ouchisinko Chemical Industrial Company,Ltd. of Tokyo, Japan, and MBT and ZMBT marketed by Akrochem Corporationof Akron, Ohio. A more complete list of commercially availableaccelerators is given in The Vanderbilt Rubber Handbook: 13^(th) Edition(1990, R.T. Vanderbilt Co.), pp. 296-330, in Encyclopedia of PolymerScience and Technology, Vol. 12 (1970, John Wiley & Sons), pp. 258-259,and in Rubber Technology Handbook (1980, Hanser/Gardner Publications),pp. 234-236. Preferred accelerators include 2-mercaptobenzothiazole(MBT) and its salts.

The polyalkenamer rubber composition can further incorporate from about0.1 part to about 10 parts by weight of the accelerator per 100 parts byweight of the polyalkenamer rubber. More preferably, the ballcomposition can further incorporate from about 0.2 part to about 5parts, and most preferably from about 0.5 part to about 1.5 parts, byweight of the accelerator per 100 parts by weight of the polyalkenamerrubber.

C. Synthetic and Natural Rubbers

Traditional rubber components used in golf ball applications can be usedto make golf balls according to the present invention including, withoutlimitation, both natural and synthetic rubbers, such ascis-1,4-polybutadienes, trans-1,4-polybutadienes, 1,2-polybutadienes,cis-polyisoprenes, trans-polyisoprenes, polychloroprenes, polybutylenes,styrene-butadiene rubbers, styrene-butadiene-styrene block copolymersand partially and fully hydrogenated equivalents,styrene-isoprene-styrene block copolymers and partially and fullyhydrogenated equivalents, nitrile rubbers, silicone rubbers, andpolyurethanes, as well as mixtures of these materials. Polybutadienerubbers, especially 1,4-polybutadiene rubbers containing at least 40 mol%, and more preferably 80 to 100 mol % of cis-1,4 bonds, are preferredbecause of their high rebound resilience, moldability, and high strengthafter vulcanization. The polybutadiene component may be purchased, ifcommercially available, or synthesized by methods now known or hereafterdeveloped, including using rare earth-based catalysts, nickel-basedcatalysts, or cobalt-based catalysts, that conventionally are used inthis field. Polybutadiene obtained by using lanthanum rare earth-basedcatalysts usually employ a combination of a lanthanum rare earth (atomicnumber of 57 to 71) compound, but particularly preferred is a neodymiumcompound.

The 1,4-polybutadiene rubbers have a molecular weight distribution(Mw/Mn) of from about 1.2 to about 4.0, preferably from about 1.7 toabout 3.7, even more preferably from about 2.0 to about 3.5, and mostpreferably from about 2.2 to about 3.2. The polybutadiene rubbers have aMooney viscosity (ML₁₊₄ (100° C.)) of from about −10 to about 80,preferably from about 20 to about 70, even more preferably from about 30to about 60, and most preferably from about 35 to about 50. “Mooneyviscosity” refers to an industrial index of viscosity as measured with aMooney viscometer, which is a type of rotary plastometer (see JISK6300). This value is represented by the symbol ML₁₊₄ (100° C.), wherein“M” stands for Mooney viscosity, “L” stands for large rotor (L-type),“1+4” stands for a pre-heating time of 1 minute and a rotor rotationtime of 4 minutes, and “100° C.” indicates that measurement was carriedout at a temperature of 100° C.

Examples of 1,2-polybutadienes having differing tacticity, all of whichare suitable as unsaturated polymers for use in the present invention,are atactic 1,2-polybutadienes, isotactic 1,2-polybutadienes, andsyndiotactic 1,2-polybutadienes. Syndiotactic 1,2-polybutadienes havingcrystallinity suitable for use as an unsaturated polymer in compositionswithin the scope of the present invention are polymerized from a1,2-addition of butadiene. Golf balls within the scope of the presentinvention include syndiotactic 1,2-polybutadienes having crystallinityand greater than about 70% of 1,2-bonds, more preferably greater thanabout 80% of 1,2-bonds, and most preferably greater than about 90% of1,2-bonds. Also, golf balls within the scope of the present inventionnot only have such crystallinity but also have a mean molecular weightof between from about 10,000 to about 350,000, more preferably betweenfrom about 50,000 to about 300,000, more preferably between from about80,000 to about 200,000, and most preferably between from about 10,000to about 150,000. Examples of suitable syndiotactic 1,2-polybutadieneshaving crystallinity suitable for use in golf balls within the scope ofthe present invention are sold under the trade names RB810, RB820, andRB830 by JSR Corporation of Tokyo, Japan. These have more than 90% of1,2 bonds, a mean molecular weight of approximately 120,000, andcrystallinity between about 15% and about 30%.

D. Thermoplastic Materials

1. Olefinic Thermoplastic Elastomers

Examples of olefinic thermoplastic elastomers include, withoutlimitation, metallocene-catalyzed polyolefins, ethylene-octenecopolymers, ethylene-butene copolymers, and ethylene-propylenecopolymers all with or without controlled tacticity as well as blends ofpolyolefins having ethyl-propylene-non-conjugated diene terpolymers,rubber-based copolymers, and dynamically vulcanized rubber-basedcopolymers. Examples of such polymers that are commercially availableinclude products sold under the trade names SANTOPRENE, DYTRON,VISTAFLEX, and VYRAM by Advanced Elastomeric Systems of Houston, Tex.,and SARLINK by DSM of Haarlen, the Netherlands.

2. Co-Polyester Thermoplastic Elastomers

Examples of copolyester thermoplastic elastomers include polyether esterblock copolymers, polylactone ester block copolymers, and aliphatic andaromatic dicarboxylic acid copolymerized polyesters. Polyether esterblock copolymers are copolymers comprising polyester hard segmentspolymerized from a dicarboxylic acid and a low molecular weight diol,and polyether soft segments polymerized from an alkylene glycol having 2to 10 atoms. Polylactone ester block copolymers are copolymers havingpolylactone chains instead of polyether as the soft segments discussedabove for polyether ester block copolymers. Aliphatic and aromaticdicarboxylic copolymerized polyesters are copolymers of an acidcomponent selected from aromatic dicarboxylic acids, such asterephthalic acid and isophthalic acid, and aliphatic acids having 2 to10 carbon atoms with at least one diol component, selected fromaliphatic and alicyclic diols having 2 to 10 carbon atoms. Blends ofaromatic polyester and aliphatic polyester also may be used for these.Examples of these include products marketed under the trade names HYTRELby E.I. DuPont de Nemours & Company, and SKYPEL by S.K. Chemicals ofSeoul, South Korea.

3. Other Thermoplastic Elastomers

Examples of other thermoplastic elastomers include multiblock,rubber-based copolymers, particularly those in which the rubber blockcomponent is based on butadiene, isoprene, or ethylene/butylene. Thenon-rubber repeating units of the copolymer may be derived from anysuitable monomer, including meth(acrylate) esters, such as methylmethacrylate and cyclohexylmethacrylate, and vinyl arylenes, such asstyrene. Styrenic block copolymers are copolymers of styrene withbutadiene, isoprene, or a mixture of the two. Additional unsaturatedmonomers may be added to the structure of the styrenic block copolymeras needed for property modification of the resulting SBC/urethanecopolymer. The styrenic block copolymer can be a diblock or a triblockstyrenic polymer. Examples of such styrenic block copolymers aredescribed in, for example, U.S. Pat. No. 5,436,295 to Nishikawa et al.,which is incorporated herein by reference. The styrenic block copolymercan have any known molecular weight for such polymers, and it canpossess a linear, branched, star, dendrimeric or combination molecularstructure. The styrenic block copolymer can be unmodified by functionalgroups, or it can be modified by hydroxyl group, carboxyl group, orother functional groups, either in its chain structure or at one or moreterminus. The styrenic block copolymer can be obtained using any commonprocess for manufacture of such polymers. The styrenic block copolymersalso may be hydrogenated using well-known methods to obtain a partiallyor fully saturated diene monomer block. Examples of styrenic copolymersinclude, without limitation, resins manufactured by Kraton Polymers(formerly of Shell Chemicals) under the trade names KRATON D (forstyrene-butadiene-styrene and styrene-isoprene-styrene types), andKRATON G (for styrene-ethylene-butylene-styrene andstyrene-ethylene-propylene-styrene types) and Kuraray under the tradename SEPTON. Examples of randomly distributed styrenic polymers includeparamethylstyrene-isobutylene (isobutene) copolymers developed byExxonMobil Chemical Corporation and styrene-butadiene random copolymersdeveloped by Chevron Phillips Chemical Corporation.

Examples of other thermoplastic elastomers suitable as additionalpolymer components in the present invention include those havingfunctional groups, such as carboxylic acid, maleic anhydride, glycidyl,norbonene, and hydroxyl functionalities. An example of these includes ablock polymer having at least one polymer block A comprising an aromaticvinyl compound and at least one polymer block B comprising a conjugateddiene compound, and having a hydroxyl group at the terminal blockcopolymer, or its hydrogenated product. An example of this polymer issold under the trade name SEPTON HG-252 by Kuraray Company of Kurashiki,Japan. Other examples of these include: maleic anhydride functionalizedtriblock copolymer consisting of polystyrene end blocks andpoly(ethylene/butylene), sold under the trade name KRATON FG 1901X byShell Chemical Company; maleic anhydride modified ethylene-vinyl acetatecopolymer, sold under the trade name FUSABOND by E.I. DuPont de Nemours& Company; ethylene-isobutyl acrylate-methacrylic acid terpolymer, soldunder the trade name NUCREL by E.I. DuPont de Nemours & Company;ethylene-ethyl acrylate-methacrylic anhydride terpolymer, sold under thetrade name BONDINE AX 8390 and 8060 by Sumitomo Chemical Industries;brominated styrene-isobutylene copolymers sold under the trade nameBROMO XP-50 by Exxon Mobil Corporation; and resins having glycidyl ormaleic anhydride functional groups sold under the trade name LOTADER byElf Atochem of Puteaux, France.

4. Polyamides

Examples of polyamides within the scope of the present invention includeresins obtained by: (1) polycondensation of (a) a dicarboxylic acid,such as oxalic acid, adipic acid, sebacic acid, terephthalic acid,isophthalic acid, or 1,4-cyclohexanedicarboxylic acid, with (b) adiamine, such as ethylenediamine, tetramethylenediamine,pentamethylenediamine, hexamethylenediamine, decamethylenediamine,1,4-cyclohexyldiamine or m-xylylenediamine; (2) a ring-openingpolymerization of cyclic lactam, such as ε-caprolactam or ω-laurolactam;(3) polycondensation of an aminocarboxylic acid, such as 6-aminocaproicacid, 9-aminononanoic acid, 11-aminoundecanoic acid or12-aminododecanoic acid; or (4) copolymerization of a cyclic lactam witha dicarboxylic acid and a diamine, and any combination of those Specificexamples of suitable polyamides include polyamide 6; polyamide 11;polyamide 12; polyamide 4,6; polyamide 6,6; polyamide 6,9; polyamide6,10; polyamide 6,12; PA12CX; PA12, IT; PPA; PA6, IT.

Non-limiting examples of suitable polyamides or copolymeric polyamidesfor use in the inner mantle and/or the outer mantle layer include thosesold under the trademarks PEBAX, CRISTAMID and RILSAN marketed byATOFINA Chemicals of Philadelphia, Pa.; GRILAMID marketed by EMS CHEMIEof Sumter, S.C.; TROGAMID marketed by Degussa of Dusseldorf, Germany;and ZYTEL marketed by E.I. DuPont de Nemours & Co. of Wilmington, Del.

5. Polyamide Elastomer

Examples of polyamide elastomers within the scope of the presentinvention include polyether amide elastomers, which result from thecopolycondensation of polyamide blocks having reactive chain ends withpolyether blocks having reactive chain ends, including: 1) polyamideblocks of diamine chain ends with polyoxyalkylene sequences ofdicarboxylic chain ends; 2) polyamide blocks of dicarboxylic chain endswith polyoxyalkylene sequences of diamine chain ends obtained bycyanoethylation and hydrogenation of polyoxyalkylene alpha-omegadihydroxylated aliphatic sequences known as polyether diols; and 3)polyamide blocks of dicarboxylic chain ends with polyether diols, theproducts obtained, in this particular case, being polyetheresteramides.

The polyamide blocks of dicarboxylic chain ends come, for example, fromthe condensation of alpha-omega aminocarboxylic acids of lactam or ofcarboxylic diacids and diamines in the presence of a carboxylic diacidwhich limits the chain length. The molecular weight of the polyamidesequences preferably is between about 300 and about 15,000, and morepreferably between about 600 and about 5,000. The molecular weight ofthe polyether sequences preferably is between about 100 and about 6,000,and more preferably between about 200 and about 3,000.

The amide block polyethers also may comprise randomly distributed units.These polymers may be prepared by the simultaneous reaction of polyetherand precursor of polyamide blocks.

For example, the polyether diol may react with a lactam (or alpha-omegaamino acid) and a diacid which limits the chain in the presence ofwater. A polymer is obtained having mainly polyether blocks, polyamideblocks of very variable length, but also the various reactive groupshaving reacted in a random manner and which are distributedstatistically along the polymer chain.

Suitable amide block polyethers include, without limitation, thosedisclosed in U.S. Pat. Nos. 4,331,786, 4,115,475, 4,195,015, 4,839,441,4,864,014, 4,230,838, and 4,332,920, which are incorporated herein intheir entireties by reference. The polyether may be, for example, apolyethylene glycol (PEG), a polypropylene glycol (PPG), or apolytetramethylene glycol (PTMG), also designated aspolytetrahydrofurane (PTHF).

The polyether blocks may be along the polymer chain in the form of diolsor diamines. However, for reasons of simplification, they are designatedPEG blocks, or PPG blocks, or also PTMG blocks.

It is also within the scope of the disclosed embodiments that thepolyether block comprises different units such as units, which derivefrom ethylene glycol, propylene glycol, or tetramethylene glycol.

The amide block polyether comprises at least one type of polyamide blockand one type of polyether block. Mixing two or more polymers withpolyamide blocks and polyether blocks also may be used. It also cancomprise any amide structure made from the method described on theabove.

Preferably, the amide block polyether is such that it represents themajor component in weight, i.e., that the amount of polyamide which isunder the block configuration and that which is eventually distributedstatistically in the chain represents 50 weight percent or more of theamide block polyether. Advantageously, the amount of polyamide and theamount of polyether is in a ratio (polyamide/polyether) of about 1:1 toabout 3:1.

One type of polyetherester elastomer is the family of Pebax, which areavailable from Elf-Atochem Company. Preferably, the choice can be madefrom among Pebax 2533, 3533, 4033, 1205, 7033, and 7233. Blends orcombinations of Pebax 2533, 3533, 4033, 1205, 7033, and 7233 also can beprepared, as well. Pebax 2533 has a hardness of about 25 shore D(according to ASTM D-2240), a Flexural Modulus of about 2.1 kpsi(according to ASTM D-790), and a Bayshore resilience of about 62%(according to ASTM D-2632). Pebax 3533 has a hardness of about 35 shoreD (according to ASTM D-2240), a Flexural Modulus of about 2.8 kpsi(according to ASTM D-790), and a Bayshore resilience of about 59%(according to ASTM D-2632). Pebax 7033 has a hardness of about 69 shoreD (according to ASTM D-2240) and a Flexural Modulus of about 67 kpsi(according to ASTM D-790). Pebax 7333 has a hardness of about 72 shore D(according to ASTM D-2240) and a Flexural Modulus of about 107 kpsi(according to ASTM D-790).

Specific examples of suitable polyamides also include Nylon 6, Nylon 66,Nylon 610, Nylon 11, Nylon 12, copolymerized Nylon, Nylon MXD6, andNylon 46.

6. Polyurethanes

Another example of an additional polymer component includespolyurethanes, which are the reaction product of a diol or polyol and anisocyanate, with or without a chain extender. Polyurethanes aredescribed in the patent literature, and some are known for use in makinggolf ball cores. See, for example, Vedula et al., U.S. Pat. No.5,959,059.

Isocyanates used for making the urethanes of the present inventionencompass diisocyanates and polyisocyanates. Examples of suitableisocyanates include the following: trimethylene diisocyanates,tetramethylene diisocyanates, pentamethylene diisocyanates,hexamethylene diisocyanates, ethylene diisocyanates, diethylidenediisocyanates, propylene diisocyanates, butylene diisocyanates,bitolylene diisocyanates, tolidine isocyanates, isophoronediisocyanates, dimeryl diisocyanates, dodecane-1,12-diisocyanates,1,10-decamethylene diisocyanates, cyclohexylene-1,2-diisocyanates,1-chlorobenzene-2,4-diisocyanates, furfurylidene diisocyanates,2,4,4-trimethyl hexamethylene diisocyanates 2,2,4-trimethylhexamethylene diisocyanates, dodecamethylene diisocyanates,1,3cyclopentane diisocyanates, 1,3-cyclohexane diisocyanates,1,3-cyclobutane diisocyanates, 1,4-cyclohexane diisocyanates,4,4′-methylenebis(cyclohexyl isocyanates), 4,4′-methylenebis(phenylisocyanates), 1-methyl-2,4-cyclohexane diisocyanates,1-methyl-2,6-cyclohexane diisocyanates,1,3-bis(isocyanato-methyl)cyclohexanes,1,6-diisocyanato-2,2,4,4-tetra-methylhexanes,1,6-diisocyanato-2,4,4-tetra-trimethylhexanes,trans-cyclohexane-1,4-diisocyanates,3-isocyanato-methyl-3,5,5-trimethylcyclohexyl isocyanates,1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexanes, cyclohexylisocyanates, dicyclohexylmethane 4,4′-diisocyanates,1,4-bis(isocyanatomethyl)cyclohexanes, m-phenylene diisocyanate,m-xylylene diisocyanate, m-tetramethylxylylene diisocyanates,p-phenylene diisocyanate, p,p′-biphenyl diisocyanates,3,3′-dimethyl-4,4′-biphenylene diisocyanates,3,3′-dimethoxy-4,4′-biphenylene diisocyanates,3,3′-diphenyl-4,4′-biphenylene diisocyanates, 4,4′-biphenylenediisocyanates, 3,3′-dichloro-4,4′-biphenylene diisocyanates,1,5-naphthalene diisocyanates, 4-chloro-1,3-phenylene diisocyanates,1,5-tetrahydronaphthalene diisocyanates, meta-xylene diisocyanates,2,4-toluene diisocyanates, 2,4′-diphenylmethane diisocyanates,2,4-chlorophenylene diisocyanates, 4,4′-diphenylmethane diisocyanates,p,p′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanates,2,6-tolylene diisocyanates, 2,2-diphenylpropane-4,4′-diisocyanate,4,4′-toluidine diisocyanates, dianisidine diisocyanates, 4,4′-diphenylether diisocyanates, 1,3-xylylene diisocyanates, 1,4-naphthylenediisocyanates, azobenzene-4,4′-diisocyanates, diphenylsulfone-4,4′-diisocyanates, triphenylmethane 4,4′,4″-triisocyanates,isocyanatoethyl methacrylates,3-isopropenyl-α,α-dimethylbenzyl-isocyanates, dichlorohexamethylenediisocyanates, ω,ω′-diisocyanato-1,4-diethylbenzenes, polymethylenepolyphenylene polyisocyanates, polybutylene diisocyanates, isocyanuratemodified compounds, and carbodiimide modified compounds, as well asbiuret modified compounds of the above polyisocyanates. Each isocyanatemay be used either alone or in combination with one or more otherisocyanates. These isocyanate mixtures can include triisocyanates, suchas biuret of hexamethylene diisocyanate and triphenylmethanetriisocyanate, and polyisocyanates, such as polymeric diphenylmethanediisocyanate.

Polyols used for making the polyurethane in the copolymer includepolyester polyols, polyether polyols, polycarbonate polyols andpolybutadiene polyols. Polyester polyols are prepared by condensation orstep-growth polymerization utilizing diacids. Primary diacids forpolyester polyols are adipic acid and isomeric phthalic acids. Adipicacid is used for materials requiring added flexibility, whereas phthalicanhydride is used for those requiring rigidity. Some examples ofpolyester polyols include poly(ethylene adipate) (PEA), poly(diethyleneadipate) (PDA), poly(propylene adipate) (PPA), poly(tetramethyleneadipate) (PBA), poly(hexamethylene adipate) (PHA), poly(neopentyleneadipate) (PNA), polyols composed of 3-methyl-1,5-pentanediol and adipicacid, random copolymer of PEA and PDA, random copolymer of PEA and PPA,random copolymer of PEA and PBA, random copolymer of PHA and PNA,caprolactone polyol obtained by the ring-opening polymerization ofε-caprolactone, and polyol obtained by opening the ring ofβ-methyl-δ-valerolactone with ethylene glycol can be used either aloneor in a combination thereof. Additionally, polyester polyols may becomposed of a copolymer of at least one of the following acids and atleast one of the following glycols. The acids include terephthalic acid,isophthalic acid, phthalic anhydride, oxalic acid, malonic acid,succinic acid, pentanedioic acid, hexanedioic acid, octanedioic acid,nonanedioic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioicacid, dimer acid (a mixture), p-hydroxybenzoate, trimellitic anhydride,ε-caprolactone, and β-methyl-δ-valerolactone. The glycols includesethylene glycol, propylene glycol, butylene glycol, pentylene glycol,1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentylene glycol,polyethylene glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol, pentaerythritol, and 3-methyl-1,5-pentanediol.

Polyether polyols are prepared by the ring-opening additionpolymerization of an alkylene oxide (e.g. ethylene oxide and propyleneoxide) with an initiator of a polyhydric alcohol (e.g. diethyleneglycol), which has an active hydrogen. Specifically, polypropyleneglycol (PPG), polyethylene glycol (PEG) or propylene oxide-ethyleneoxide copolymer can be obtained. Polytetramethylene ether glycol (PTMG)is prepared by the ring-opening polymerization of tetrahydrofuran,produced by dehydration of 1,4-butanediol or hydrogenation of furan.Tetrahydrofuran can form a copolymer with alkylene oxide. Specifically,tetrahydrofuran-propylene oxide copolymer or tetrahydrofuran-ethyleneoxide copolymer can be formed. A polyether polyol may be used eitheralone or in a mixture.

Polycarbonate polyols are obtained by the condensation of a known polyol(polyhydric alcohol) with phosgene, chloroformic acid ester, dialkylcarbonate or diallyl carbonate. A particularly preferred polycarbonatepolyol contains a polyol component using 1,6-hexanediol, 1,4-butanediol,1,3-butanediol, neopentylglycol or 1,5-pentanediol. A polycarbonatepolyol can be used either alone or in a mixture.

Polybutadiene polyols include liquid diene polymer containing hydroxylgroups, and an average of at least 1.7 functional groups, and may becomposed of diene polymers or diene copolymers having 4 to 12 carbonatoms, or a copolymer of such diene with addition to polymerizableα-olefin monomer having 2 to 2.2 carbon atoms. Specific examples includebutadiene homopolymer, isoprene homopolymer, butadiene-styrenecopolymer, butadiene-isoprene copolymer, butadiene-acrylonitrilecopolymer, butadiene-2-ethyl hexyl acrylate copolymer, andbutadiene-n-octadecyl acrylate copolymer. These liquid diene polymerscan be obtained, for example, by heating a conjugated diene monomer inthe presence of hydrogen peroxide in a liquid reactant. A polybutadienepolyol can be used either alone or in a mixture.

Urethanes used to practice the present invention also may incorporatechain extenders. Non-limiting examples of these extenders includepolyols, polyamine compounds, and mixtures of these. Polyol extendersmay be primary, secondary, or tertiary polyols. Specific examples ofmonomers of these polyols include: trimethylolpropane (TMP), ethyleneglycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol,1,6-hexanediol, propylene glycol, dipropylene glycol, 1,2-butanediol,1,3-butanediol, 2,3-butanediol, 1,2-pentanediol, 2,3-pentanediol,2,5-hexanediol, 2,4-hexanediol, 2-ethyl-1,3-hexanediol, cyclohexanediol,and 2-ethyl-2-(hydroxymethyl)-1,3-propanediol.

Suitable polyamines that may be used as chain extenders include primary,secondary and tertiary amines. Polyamines have two or more aminefunctional groups. Examples of polyamines include, without limitation:aliphatic diamines, such as tetramethylenediamine,pentamethylenediamine, hexamethylenediamine; alicyclic diamines, such as3,3′-dimethyl-4,4′-diamino-dicyclohexyl methane; or aromatic diamines,such as 4,4′-methylene bis-2-chloroaniline, dimethylthio-2,4-toluenediamine, diethyl-2,4-toluene diamine,2,2′,3,3′-tetrachloro-4,4′-diaminophenyl methane,p,p′-methylenedianiline, p-phenylenediamine or 4,4′-diaminodiphenyl; and2,4,6-tris(dimethylaminomethyl) phenol, and any and all combinationsthereof. A chain extender may be used either alone or in a mixture.

7. Ethylenically Unsaturated Thermoplastic Elastomers

Another family of thermoplastic elastomers for use in the golf balls ofthe present invention are polymers of (i) ethylene and/or an alphaolefin; and (ii) an α,β-ethylenically unsaturated C₃-C₂₀ carboxylic acidor anhydride, or an α,β-ethylenically unsaturated C₃-C₂₀ sulfonic acidor anhydride or an α,β-ethylenically unsaturated C₃-C₂₀ phosphoric acidor anhydride and, optionally iii) a C₁-C₁₀ ester of an α,β-ethylenicallyunsaturated C₃-C₂₀ carboxylic acid or a C₁-C₁₀ ester of anα,β-ethylenically unsaturated C₃-C₂₀ sulfonic acid or a C₁-C₁₀ ester ofan α,β-ethylenically unsaturated C₃-C₂₀ phosphoric acid.

Preferably, the alpha-olefin has from 2 to 10 carbon atoms and ispreferably ethylene, and the unsaturated carboxylic acid is a carboxylicacid having from about 3 to 8 carbons. Examples of such acids includeacrylic acid, methacrylic acid, ethacrylic acid, chloroacrylic acid,crotonic acid, maleic acid, fumaric acid, and itaconic acid, withacrylic acid and methacrylic acid being preferred. Preferably, thecarboxylic acid ester of if present may be selected from the groupconsisting of vinyl esters of aliphatic carboxylic acids wherein theacids have 2 to 10 carbon atoms and vinyl ethers wherein the alkylgroups contain 1 to 10 carbon atoms.

Examples of such polymers suitable for use include, but are not limitedto, an ethylene/acrylic acid copolymer, an ethylene/methacrylic acidcopolymer, an ethylene/itaconic acid copolymer, an ethylene/maleic acidcopolymer, an ethylene/methacrylic acid/vinyl acetate copolymer, anethylene/acrylic acid/vinyl alcohol copolymer, and the like.

Most preferred are ethylene/(meth)acrylic acid copolymers andethylene/(meth)acrylic acid/alkyl(meth)acrylate terpolymers, or ethyleneand/or propylene maleic anhydride copolymers and terpolymers.

The acid content of the polymer may contain anywhere from 1 to 30percent by weight acid. In some instances, it is preferable to utilize ahigh acid copolymer (i.e., a copolymer containing greater than 16% byweight acid, preferably from about 17 to about 25 weight percent acid,and more preferably about 20 weight percent acid).

Examples of such polymers which are commercially available include, butare not limited to, the Escor® 5000, 5001, 5020, 5050, 5070, 5100, 5110and 5200 series of ethylene-acrylic acid copolymers sold by Exxon andthe PRIMACOR® 1321, 1410, 1410-XT, 1420, 1430, 2912, 3150, 3330, 3340,3440, 3460, 4311 and 4608 series of ethylene-acrylic acid copolymerssold by The Dow Chemical Company, Midland, Mich.

Also included are the bimodal ethylene/carboxylic acid polymers asdescribed in U.S. Pat. No. 6,562,906, the entire contents of which areherein incorporated by reference. These polymers compriseethylene/α,β-ethylenically unsaturated C₃₋₈ carboxylic acid highcopolymers, particularly ethylene(meth)acrylic acid copolymers andethylene, alkyl(meth)acrylate, (meth)acrylic acid terpolymers, havingmolecular weights of about 80,000 to about 500,000 which are meltblended with ethylene/α,β-ethylenically unsaturated C₃₋₈ carboxylic acidcopolymers, particularly ethylene/(meth)acrylic acid copolymers havingmolecular weights of about 2,000 to about 30,000.

8. Ionomers

The core, cover layer and, optionally, one or more inner cover layersgolf ball embodiments of the present invention may further comprise oneor more ionomer resins. One family of such resins was developed in themid-1960's, by E.I. DuPont de Nemours and Co., and sold under thetrademark SURLYN®. Preparation of such ionomers is well known, forexample see U.S. Pat. No. 3,264,272 (the entire contents of which areherein incorporated by reference). Generally speaking, most commercialionomers are unimodal and consist of a polymer of a mono-olefin, e.g.,an alkene, with an unsaturated mono- or dicarboxylic acids having 3 to12 carbon atoms. An additional monomer in the form of a mono- ordicarboxylic acid ester also may be incorporated in the formulation as aso-called “softening comonomer”. The incorporated carboxylic acid groupsare then neutralized by a basic metal ion salt, to form the ionomer. Themetal cations of the basic metal ion salt used for neutralizationinclude Li⁺, Na⁺, K⁺, Zn²⁺, ca²⁺, Co²⁺, Ni²⁺, cu²⁺, Pb²⁺, and Mg²⁺, withthe Li⁺, Na⁺, Ca²⁺, Zn²⁺, and Mg²⁺ being preferred. The basic metal ionsalts include those of, for example, formic acid, acetic acid, nitricacid, and carbonic acid, hydrogen carbonate salts, oxides, hydroxides,and alkoxides.

The first commercially available ionomer resins contained up to 16weight percent acrylic or methacrylic acid, although it also was wellknown at that time that, as a general rule, the hardness of these covermaterials could be increased with increasing acid content. Hence, inResearch Disclosure 29703, published in January 1989, DuPont disclosedionomers based on ethylene/acrylic acid or ethylene/methacrylic acidcontaining acid contents of greater than 15 weight percent. In this samedisclosure, DuPont also taught that such so called “high acid ionomers”had significantly improved stiffness and hardness and thus could beadvantageously used in golf ball construction, when used either singlyor in a blend with other ionomers.

More recently, high acid ionomers are typically defined as those ionomerresins with acrylic or methacrylic acid units present from 16 weightpercent to about 35 weight percent in the polymer. Generally, such ahigh acid ionomer will have a flexural modulus from about 50,000 psi toabout 125,000 psi.

Ionomer resins may further comprise a softening comonomer, present fromabout 10 weight percent to about 50 weight percent in the polymer, havea flexural modulus from about 2,000 psi to about 10,000 psi, and aresometimes referred to as “soft” or “very low modulus” ionomers. Typicalsoftening comonomers include n-butyl acrylate, iso-butyl acrylate,n-butyl methacrylate, methyl acrylate and methyl methacrylate.

Today, there are a wide variety of commercially available ionomer resinsbased both on copolymers of ethylene and (meth)acrylic acid orterpolymers of ethylene and (meth)acrylic acid and (meth)acrylate, manyof which can be used as a golf ball component. The properties of theseionomer resins can vary widely due to variations in acid content,softening comonomer content, the degree of neutralization, and the typeof metal ion used in the neutralization. The full range commerciallyavailable typically includes ionomers of polymers of general formula,E/X/Y, wherein E is ethylene, X is a C₃ to C₈ α,β-ethylenicallyunsaturated carboxylic acid, such as acrylic or methacrylic acid, and ispresent in an amount from about 2 to about 30 weight percent of theE/X/Y copolymer, and Y is a softening comonomer selected from the groupconsisting of alkyl acrylate and alkyl methacrylate, such as methylacrylate or methyl methacrylate, and wherein the alkyl groups have from1-8 carbon atoms, Y is in the range of 0 to about 50 weight percent ofthe E/X/Y copolymer, and wherein the acid moiety is neutralized fromabout 1% to about 90% to form an ionomer with a cation such as lithium,sodium, potassium, magnesium, calcium, barium, lead, tin, zinc oraluminum, or a combination of such cations.

The ionomer also may be a so-called bimodal ionomer as described in U.S.Pat. No. 6,562,906 (the entire contents of which are herein incorporatedby reference). These ionomers are bimodal as they are prepared fromblends comprising polymers of different molecular weights. Specificallythey include bimodal polymer blend compositions comprising:

a high molecular weight component having molecular weight of about80,000 to about 500,000 and comprising one or moreethylene/α,β-ethylenically unsaturated C₃₋₈ carboxylic acid copolymersand/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acidterpolymers; the high molecular weight component being partiallyneutralized with metal ions selected from the group consisting oflithium, sodium, potassium, zinc, calcium, magnesium, and a mixture ofany these; and

a low molecular weight component having a molecular weight of from about2,000 to about 30,000 and comprising one or moreethylene/α,β-ethylenically unsaturated C₃₋₈ carboxylic acid copolymersand/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acidterpolymers; the low molecular weight component being partiallyneutralized with metal ions selected from the group consisting oflithium, sodium, potassium, zinc, calcium, magnesium, and a mixture ofany these.

In addition to the unimodal and bimodal ionomers, also included are theso-called “modified ionomers” examples of which are described in U.S.Pat. Nos. 6,100,321, 6,329,458 and 6,616,552 and U.S. Patent PublicationUS 2003/0158312 A1, the entire contents of all of which are hereinincorporated by reference.

The modified unimodal ionomers are prepared by mixing:

an ionomeric polymer comprising ethylene, from 5 to 25 weight percent(meth)acrylic acid, and from 0 to 40 weight percent of a (meth)acrylatemonomer, the ionomeric polymer neutralized with metal ions selected fromthe group consisting of lithium, sodium, potassium, zinc, calcium,magnesium, and a mixture of any these, and

from about 5 to about 40 weight percent (based on the total weight ofsaid modified ionomeric polymer) of one or more fatty acids or metalsalts of said fatty acid, the metal selected from the group consistingof calcium, sodium, zinc, potassium, and lithium, barium and magnesiumand the fatty acid preferably being stearic acid.

The modified bimodal ionomers, which are ionomers derived from theearlier described bimodal ethylene/carboxylic acid polymers (asdescribed in U.S. Pat. No. 6,562,906, the entire contents of which areherein incorporated by reference), are prepared by mixing:

a. a high molecular weight component having molecular weight of about80,000 to about 500,000 and comprising one or moreethylene/α,β-ethylenically unsaturated C₃₋₈ carboxylic acid copolymersand/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acidterpolymers; the high molecular weight component being partiallyneutralized with metal ions selected from the group consisting oflithium, sodium, zinc, calcium, potassium, magnesium, and a mixture ofany of these;

b. a low molecular weight component having a molecular weight of aboutfrom about 2,000 to about 30,000 and comprising one or moreethylene/α,β-ethylenically unsaturated C₃₋₈ carboxylic acid copolymersand/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acidterpolymers; the low molecular weight component being partiallyneutralized with metal ions selected from the group consisting oflithium, sodium, zinc, calcium, potassium, magnesium, and a mixture ofany of these; and

c. from about 5 to about 40 weight percent (based on the total weight ofsaid modified ionomeric polymer) of one or more fatty acids or metalsalts of the fatty acid, the metal selected from the group consisting ofcalcium, sodium, zinc, potassium and lithium, barium and magnesium andthe fatty acid preferably being stearic acid.

The fatty or waxy acid salts utilized in the various modified ionomersare composed of a chain of alkyl groups containing from about 4 to 75carbon atoms (usually even numbered) and characterized by a —COOHterminal group. The generic formula for all fatty and waxy acids aboveacetic acid is CH₃ (CH₂)_(X) COOH, wherein the carbon atom countincludes the carboxyl group. The fatty or waxy acids utilized to producethe fatty or waxy acid salts modifiers may be saturated or unsaturated,and they may be present in solid, semi-solid or liquid form.

Examples of suitable saturated fatty acids, i.e., fatty acids in whichthe carbon atoms of the alkyl chain are connected by single bonds,include but are not limited to, stearic acid (C₁₈, i.e., CH₃ (CH₂)₁₆COOH), palmitic acid (C₁₆, i.e., CH₃ (CH₂)₁₄ COOH), pelargonic acid (C₉,i.e., CH₃ (CH₂)₇ COOH) and lauric acid (C₁₂, i.e., CH₃ (CH₂)₁₀ OCOOH).Examples of suitable unsaturated fatty acids, i.e., a fatty acid inwhich there are one or more double bonds between the carbon atoms in thealkyl chain, include but are not limited to oleic acid (C₁₈, i.e.,CH₃(CH₂)₇CH:CH(CH₂)₇COOH).

The source of the metal ions used to produce the metal salts of thefatty or waxy acid salts used in the various modified ionomers aregenerally various metal salts, which provide the metal ions capable ofneutralizing, to various extents, the carboxylic acid groups of thefatty acids. These include the sulfate, carbonate, acetate andhydroxylate salts of zinc, sodium, lithium, potassium, barium, calciumand magnesium.

Since the fatty acid salts modifiers comprise various combinations offatty acids neutralized with a large number of different metal ions,several different types of fatty acid salts may be utilized in theinvention, including metal stearates, laureates, oleates, andpalmitates, with calcium, zinc, sodium, lithium, potassium and magnesiumstearate being preferred, and calcium and sodium stearate being mostpreferred.

The fatty or waxy acid or metal salt of the fatty or waxy acid ispresent in the modified ionomeric polymers in an amount of from about 5to about 40, preferably from about 7 to about 35, more preferably fromabout 8 to about 20 weight percent (based on the total weight of saidmodified ionomeric polymer).

As a result of the addition of the one or more metal salts of a fatty orwaxy acid, from about 40 to 100, preferably from about 50 to 100, morepreferably from about 70 to 100 percent of the acidic groups in thefinal modified ionomeric polymer composition are neutralized by a metalion.

An example of such a modified ionomer polymer is DuPont® HPF-1000available from E.I. DuPont de Nemours and Co. Inc.

9. Silicone Materials

Silicone materials also are well suited for blending into compositionswithin the scope of the present invention. These can be monomers,oligomers, prepolymers, or polymers, with or without additionalreinforcing filler. One type of silicone material that is suitable canincorporate at least 1 alkenyl group having at least 2 carbon atoms intheir molecules. Examples of these alkenyl groups include, but are notlimited to, vinyl, allyl, butenyl, pentenyl, hexenyl and decenyl. Thealkenyl functionality can be located at any location of the siliconestructure, including one or both terminals of the structure. Theremaining (i.e., non-alkenyl) silicon-bonded organic groups in thiscomponent are independently selected from hydrocarbon or halogenatedhydrocarbon groups that contain no aliphatic unsaturation. Non-limitingexamples of these include: alkyl groups, such as methyl, ethyl, propyl,butyl, pentyl and hexyl; cycloalkyl groups, such as cyclohexyl andcycloheptyl; aryl groups, such as phenyl, tolyl and xylyl; aralkylgroups, such as benzyl and phenethyl; and halogenated alkyl groups, suchas 3,3,3-trifluoropropyl and chloromethyl. Another type of siliconematerial suitable for use in the present invention is one havinghydrocarbon groups that lack aliphatic unsaturation. Specific examplesof suitable silicones for use in making compositions of the presentinvention include the following: trimethylsiloxy-endblockeddimethylsiloxane-methylhexenylsiloxane copolymers;dimethylhexenlylsiloxy-endblocked dimethylsiloxane-methylhexenylsiloxanecopolymers; trimethylsiloxy-endblockeddimethylsiloxane-methylvinylsiloxane copolymers;trimethylsiloxy-endblockedmethylphenylsiloxane-dimethylsil-oxane-methylvinylsiloxane copolymers;dimethylvinylsiloxy-endblocked dimethylpolysiloxanes;dimethylvinylsiloxy-endblocked dimethylsiloxane-methylvinylsiloxanecopolymers; dimethylvinylsiloxy-endblocked methylphenylpolysiloxanes;dimethylvinylsiloxy-endblockedmethylphenylsiloxane-dimethylsiloxane-methylvinylsiloxane copolymers;and the copolymers listed above, in which at least one end group isdimethylhydroxysiloxy. Commercially available silicones suitable for usein compositions within the scope of the present invention includeSilastic by Dow Corning Corp. of Midland, Mich., Blensil by GE Siliconesof Waterford, N.Y., and Elastosil by Wacker Silicones of Adrian, Mich.

10. Miscellaneous Copolymers

Other types of copolymers also can be added to compositions within thescope of the present invention. Examples of copolymers comprising epoxymonomers and which are suitable for use within the scope of the presentinvention include styrene-butadiene-styrene block copolymers, in whichthe polybutadiene block contains an epoxy group, andstyrene-isoprene-styrene block copolymers, in which the polyisopreneblock contains epoxy. Commercially available examples of these epoxyfunctional copolymers include ESBS A1005, ESBS A1010, ESBS A1020, ESBSAT018, and ESBS AT019, marketed by Daicel Chemical Industries, Ltd. ofOsaka, Japan.

V. Filler

The polymeric compositions used to prepare the golf balls of the presentinvention also can incorporate one or more fillers. Such fillers aretypically in a finely divided form, for example, in a size generallyless than about 20 mesh, preferably less than about 100 mesh U.S.standard size, except for fibers and flock, which are generallyelongated. Filler particle size will depend upon desired effect, cost,ease of addition, and dusting considerations. The appropriate amounts offiller required will vary depending on the application but typically canbe readily determined without undue experimentation.

The filler preferably is selected from the group consisting ofprecipitated hydrated silica, limestone, clay, talc, asbestos, barytes,glass fibers, aramid fibers, mica, calcium metasilicate, barium sulfate,zinc sulfide, lithopone, silicates, silicon carbide, diatomaceous earth,carbonates such as calcium or magnesium or barium carbonate, sulfatessuch as calcium or magnesium or barium sulfate, metals, includingtungsten, steel, copper, cobalt or iron, metal alloys, tungsten carbide,metal oxides, metal stearates, and other particulate carbonaceousmaterials, and any and all combinations thereof. Preferred examples offillers include metal oxides, such as zinc oxide and magnesium oxide. Inanother preferred embodiment the filler comprises a continuous ornon-continuous fiber. In another preferred embodiment the fillercomprises one or more so called nanofillers, as described in U.S. Pat.No. 6,794,447 and copending U.S. patent application Ser. No. 10/670,090filed on Sep. 24, 2003 and copending U.S. patent application Ser. No.10/926,509 filed on Aug. 25, 2004, the entire contents of each of whichare incorporated herein by reference.

Inorganic nanofiller material generally is made of clay, such ashydrotalcite, phyllosilicate, saponite, hectorite, beidellite,stevensite, vermiculite, halloysite, mica, montmorillonite,micafluoride, or octosilicate. To facilitate incorporation of thenanofiller material into a polymer material, either in preparingnanocomposite materials or in preparing polymer-based golf ballcompositions, the clay particles generally are coated or treated by asuitable compatibilizing agent. The compatibilizing agent allows forsuperior linkage between the inorganic and organic material, and it alsocan account for the hydrophilic nature of the inorganic nanofillermaterial and the possibly hydrophobic nature of the polymer.Compatibilizing agents may exhibit a variety of different structuresdepending upon the nature of both the inorganic nanofiller material andthe target matrix polymer. Non-limiting examples include hydroxy-,thiol-, amino-, epoxy-, carboxylic acid-, ester-, amide-, andsiloxy-group containing compounds, oligomers or polymers. The nanofillermaterials can be incorporated into the polymer either by dispersion intothe particular monomer or oligomer prior to polymerization, or by meltcompounding of the particles into the matrix polymer. Examples ofcommercial nanofillers are various Cloisite grades including 10A, 15A,20A, 25A, 30B, and NA+ of Southern Clay Products (Gonzales, Tex.) andthe Nanomer grades including 1.24TL and C.30EVA of Nanocor, Inc.(Arlington Heights, Ill.).

As mentioned above, the nanofiller particles have an aggregate structurewith the aggregates particle sizes in the micron range and above.However, these aggregates have a stacked plate structure with theindividual platelets being roughly from about 1 nanometer (nm) thick andfrom about 100 to about 1000 nm across. As a result, nanofillers haveextremely high surface area, resulting in high reinforcement efficiencyto the material at low loading levels of the particles. Thesub-micron-sized particles enhance the stiffness of the material,without increasing its weight or opacity and without reducing thematerial's low-temperature toughness.

Nanofillers when added into a matrix polymer, such as the polyalkenamerrubber, can be mixed in three ways. In one type of mixing there isdispersion of the aggregate structures within the matrix polymer, but onmixing no interaction of the matrix polymer with the aggregate plateletstructure occurs, and thus the stacked platelet structure is essentiallymaintained. As used herein, this type of mixing is defined as“undispersed”.

However, if the nanofiller material is selected correctly, the matrixpolymer chains can penetrate into the aggregates and separate theplatelets, and thus when viewed by transmission electron microscopy orx-ray diffraction, the aggregates of platelets are expanded. At thispoint the nanofiller is said to be substantially evenly dispersed withinand reacted into the structure of the matrix polymer. This level ofexpansion can occur to differing degrees. If small amounts of the matrixpolymer are layered between the individual platelets then, as usedherein, this type of mixing is known as “intercalation”.

In some circumstances, further penetration of the matrix polymer chainsinto the aggregate structure separates the platelets, and leads to acomplete disruption of the platelet's stacked structure in theaggregate. Thus, when viewed by transmission electron microscopy (TEM),the individual platelets are thoroughly mixed throughout the matrixpolymer. As used herein, this type of mixing is known as “exfoliated”.An exfoliated nanofiller has the platelets fully dispersed throughoutthe polymer matrix; the platelets may be dispersed unevenly butpreferably are dispersed evenly.

While not wishing to be limited to any theory, one possible explanationof the differing degrees of dispersion of such nanofillers within thematrix polymer structure is the effect of the compatibilizer surfacecoating on the interaction between the nanofiller platelet structure andthe matrix polymer. By careful selection of the nanofiller it ispossible to vary the penetration of the matrix polymer into the plateletstructure of the nanofiller on mixing. Thus, the degree of interactionand intrusion of the polymer matrix into the nanofiller controls theseparation and dispersion of the individual platelets of the nanofillerwithin the polymer matrix. This interaction of the polymer matrix andthe platelet structure of the nanofiller is defined herein as thenanofiller “reacting into the structure of the polymer” and thesubsequent dispersion of the platelets within the polymer matrix isdefined herein as the nanofiller “being substantially evenly dispersed”within the structure of the polymer matrix.

If no compatibilizer is present on the surface of a filler such as aclay, or if the coating of the clay is attempted after its addition tothe polymer matrix, then the penetration of the matrix polymer into thenanofiller is much less efficient, very little separation and nodispersion of the individual clay platelets occurs within the matrixpolymer.

Physical properties of the polymer will change with the addition ofnanofiller. The physical properties of the polymer are expected toimprove even more as the nanofiller is dispersed into the polymer matrixto form a nanocomposite.

Materials incorporating nanofiller materials can provide these propertyimprovements at much lower densities than those incorporatingconventional fillers. For example, a nylon-6 nanocomposite materialmanufactured by RTP Corporation of Wichita, Kans., uses a 3% to 5% clayloading and has a tensile strength of 11,800 psi and a specific gravityof 1.14, while a conventional 30% mineral-filled material has a tensilestrength of 8,000 psi and a specific gravity of 1.36. Usingnanocomposite materials with lower inorganic materials loadings thanconventional fillers provides the same properties, and this allowsproducts comprising nanocomposite fillers to be lighter than those withconventional fillers, while maintaining those same properties.

Nanocomposite materials are materials incorporating from about 0.1% toabout 20%, preferably from about 0.1% to about 15%, and most preferablyfrom about 0.1% to about 10% of nanofiller reacted into andsubstantially dispersed through intercalation or exfoliation into thestructure of an organic material, such as a polymer, to providestrength, temperature resistance, and other property improvements to theresulting composite. Descriptions of particular nanocomposite materialsand their manufacture can be found in U.S. Pat. No. 5,962,553 toEllsworth, U.S. Pat. No. 5,385,776 to Maxfield et al., and U.S. Pat. No.4,894,411 to Okada et al. Examples of nanocomposite materials currentlymarketed include M1030D, manufactured by Unitika Limited, of Osaka,Japan, and 1015C2, manufactured by UBE America of New York, N.Y.

When nanocomposites are blended with other polymer systems, thenanocomposite may be considered a type of nanofiller concentrate.However, a nanofiller concentrate may be more generally a polymer intowhich nanofiller is mixed; a nanofiller concentrate does not requirethat the nanofiller has reacted and/or dispersed evenly into the carrierpolymer.

For the polyalkenamers, the nanofiller material is added in an amount offrom about 0.1% to about 20%, preferably from about 0.1% to about 15%,and most preferably from about 0.1% to about 10% by weight of nanofillerreacted into and substantially dispersed through intercalation orexfoliation into the structure of the polyalkenamer.

If desired, the various polymer compositions used to prepare the golfballs of the present invention can additionally contain otherconventional additives such as plasticizers, pigments, antioxidants,U.V. absorbers, optical brighteners, or any other additives generallyemployed in plastics formulation or the preparation of golf balls.

Another particularly well-suited additive for use in the compositions ofthe present invention includes compounds having the general formula:

(R₂N)_(m)—R′-(X(O)_(n)OR_(y))_(m),

where R is hydrogen, or a C₁-C₂₀ aliphatic, cycloaliphatic or aromaticsystems; R′ is a bridging group comprising one or more C₁-C₂₀ straightchain or branched aliphatic or alicyclic groups, or substituted straightchain or branched aliphatic or alicyclic groups, or aromatic group, oran oligomer of up to 12 repeating units including, but not limited to,polypeptides derived from an amino acid sequence of up to 12 aminoacids; and X is C or S or P with the proviso that when X=C, n=1 and y=1and when X=S, n=2 and y=1, and when X=P, n=2 and y=2. Also, m=1-3. Thesematerials are more fully described in copending U.S. patent applicationSer. No. 11/182,170, filed on Jul. 14, 2005, the entire contents ofwhich are incorporated herein by reference. These materials include,without limitation, caprolactam, oenantholactam, decanolactam,undecanolactam, dodecanolactam, caproic 6-amino acid,11-aminoundecanoicacid, 12-aminododecanoic acid, diamine hexamethylenesalts of adipic acid, azeleic acid, sebacic acid and 1,12-dodecanoicacid and the diamine nonamethylene salt of adipic acid., 2-aminocinnamicacid, L-aspartic acid, 5-aminosalicylic acid, aminobutyric acid;aminocaproic acid; aminocapyryic acid;1-(aminocarbonyl)-1-cyclopropanecarboxylic acid; aminocephalosporanicacid; aminobenzoic acid; aminochlorobenzoic acid;2-(3-amino-4-chlorobenzoyl)benzoic acid; aminonaphtoic acid;aminonicotinic acid; aminonorbornanecarboxylic acid; aminoorotic acid;aminopenicillanic acid; aminopentenoic acid; (aminophenyl)butyric acid;aminophenyl propionic acid; aminophthalic acid; aminofolic acid;aminopyrazine carboxylic acid; aminopyrazole carboxylic acid;aminosalicylic acid; aminoterephthalic acid; aminovaleric acid; ammoniumhydrogencitrate; anthranillic acid; aminobenzophenone carboxylic acid;aminosuccinamic acid, epsilon-caprolactam; omega-caprolactam,(carbamoylphenoxy)acetic acid, sodium salt; carbobenzyloxy asparticacid; carbobenzyl glutamine; carbobenzyloxyglycine; 2-aminoethylhydrogensulfate; aminonaphthalenesulfonic acid; aminotoluene sulfonicacid; 4,4′-methylene-bis-(cyclohexylamine)carbamate and ammoniumcarbamate.

Most preferably the material is selected from the group consisting of4,4′-methylene-bis-(cyclohexylamine)carbamate (commercially availablefrom R.T. Vanderbilt Co., Norwalk Conn. under the tradename Diak® 4),11-aminoundecanoicacid, 12-aminododecanoic acid, epsilon-caprolactam;omega-caprolactam, and any and all combinations thereof.

In an especially preferred embodiment a nanofiller additive component inthe golf ball of the present invention is surface modified with acompatibilizing agent comprising the earlier described compounds havingthe general formula:

(R₂N)_(m)—R′-(X(O)_(n)OR_(y))_(m),

A most preferred embodiment would be a filler comprising a nanofillerclay material surface modified with an amino acid including12-aminododecanoic acid. Such fillers are available from Nanonocor Co.under the tradename Nanomer 1.24TL.

The filler can be blended in variable effective amounts, such as amountsof greater than 0 to at least about 80 parts, and more typically fromabout 10 parts to about 80 parts, by weight per 100 parts by weight ofthe base rubber. If desired, the rubber composition can additionallycontain effective amounts of a plasticizer, an antioxidant, and anyother additives generally used to make golf balls.

VI. Miscellaneous Additives

Golf balls within the scope of the present invention also can include,in suitable amounts, one or more additional ingredients generallyemployed in golf ball compositions. Agents provided to achieve specificfunctions, such as additives and stabilizers, can be present. Exemplarysuitable ingredients include colorants, UV stabilizers, photostabilizers, antioxidants, colorants, dispersants, mold releasingagents, processing aids, fillers, and any and all combinations thereof.

VII. Method for Making Disclosed Compositions

The disclosed polymer and/or polymer precursor/peptizer compositions inthe present invention can be formed by any suitable mixing methods. Thepolymer and peptizer composition, including cross-linking agent(s), andany other desired additives, such as an accelerator if appropriate, canbe mixed together by any suitable methods now known or hereafterdeveloped to form golf balls, with or without melting. Dry blendingequipment, such as a tumble mixer, V-blender, or ribbon blender, can beused to mix the compositions. The unsaturated polymer, peptizer, andaccelerator can be mixed together with a cross-linking agent, or eachadditive can be added in an appropriate sequence to the unsaturatedpolymer, e.g., peptizer then accelerator then cross-linking agent. Thegolf ball compositions can be mixed using a mill, internal mixer,extruder or combinations of these, with or without application ofthermal energy to produce melting. The composition can be prepared byany suitable process, such as single screw extrusion, twin-screwextrusion, banbury mixing, two-roll mill mixing, dry blending, by usinga master batch, or any combination of these techniques. The resultingcompositions can be processed by any method useful to form golf balls orgolf ball preforms, such as extrusion (or disclosed in detail inapplicants' co-pending U.S. Application No. 60/699,303, incorporatedherein by reference) profile-extrusion, pultrusion, compression molding,transfer molding, injection molding, cold-runner molding, hot-runnermolding, reaction injection molding or any combination thereof. Thepolymer/polymer modifier composition can be a blend that is notsubjected to any further crosslinking or curing; a blend that issubjected to crosslinking or curing; a blend that forms a semi- orfull-interpenetrating polymer network (IPN) upon crosslinking or curing;or a thermoplastic vulcanizate blend. The composition can be crosslinkedby any crosslinking method(s), such as, for example, using chemicalcrosslinking agents, applying thermal energy, irradiation, or acombination thereof. The crosslinking reaction can be performed duringany processing stage, such as extrusion, compression molding, transfermolding, injection molding, post-curing, or a combination thereof. Inone embodiment, the ability of the disclosed polymer and/or polymerprecursor/peptizer compositions to be injection molded and cured eithersubsequently by compression molding or actually during the injectionmolding process itself provides considerable flexibility in manufactureof the individual golf ball components.

For instance, the disclosed polymer and/or polymer precursor/peptizercompositions, including crosslinking agents, fillers and the like, canbe mixed together with or without melting individual components. Dryblending equipment, such as a tumble mixer, V-blender, ribbon blender,or two-roll mill, can be used to mix the compositions. The golf ballcompositions can also be mixed using a mill, internal mixer such as aBanbury or Farrel continuous mixer, extruder or combinations of these,with or without application of thermal energy to produce melting. Thevarious components can be mixed together with the cross-linking agents,or each additive can be added in an appropriate sequence. In anothermethod of manufacture the cross-linking agents and other components canbe added as part of a concentrate.

The resulting mixture can be subjected to, for example, a compression orinjection molding process, to obtain solid spheres for the core. Thepolymer mixture is subjected to a molding cycle in which heat andpressure are applied while the mixture is confined within a mold. Thecavity shape depends on the portion of the golf ball being formed.

Where crosslinking agents are used, the compression and heat mayliberate free radicals, such as by decomposing one or more peroxides,which initiate cross-linking. The temperature and duration of themolding cycle are selected based upon the type of crosslinking agentselected. The molding cycle may have a single molding step that isperformed at a particularly suitable temperature for fixed timeduration; the molding cycle may have plural molding steps at pluraldifferent suitable temperatures for fixed durations; the molding cyclemay include one or more steps where the temperature is increased ordecreased from an initial temperature during the molding step period;etc.

For example, one process for preparing golf ball cores comprising thedisclosed compositions comprises first mixing various core ingredientson a two-roll mill to form slugs of approximately 30-45 grams. The slugsare then compression molded in a single step at an effectivetemperature, typically between from about 150° C. to about 210° C., foran effective time period, which typically is between from about 2 toabout 12 minutes.

Alternatively, the core may be formed by first injection molding thecore composition into a mold followed by a subsequent compressionmolding step to complete the curing step. The curing time and conditionsin this step depend on the formulation of the composition used.

Alternatively, the core may be formed from a suitable composition in asingle injection molding step in which the composition is injectionmolded into a heated mold at a sufficient temperature to yield thedesired core properties. If the material is partially cured, additionalcompression molding and/or irradiation steps optionally may be used tocomplete the curing process and thereby yield the desired coreproperties.

Similarly in both intermediate layer(s) and outer cover formation, theuse of disclosed polymer/peptizer compositions allows for considerableflexibility in the layer formation steps of golf ball construction. Forinstance, finished golf balls may be prepared by initially positioning asolid preformed core in an injection molding cavity followed by uniforminjection of the intermediate or cover layer composition sequentiallyover the core to produce layers of the required thickness and ultimatelygolf balls of the required diameter. Again use of a heated injectionmold allows the temperature to be controlled sufficiently to eitherpartially or fully crosslink the material to yield the desired layerproperties. If the material is partially cured, additional compressionmolding or irradiation steps optionally may be employed to complete thecuring process to yield the desired layer properties.

Alternatively, the intermediate and/or cover layers also may be formedaround the core or intermediate layer by first forming half shells byinjection molding the polymer/polymer modifier compositions followed bya compression molding the half shells about the core or intermediatelayer to cure the layers in the final ball.

Alternatively, the intermediate and/or cover layers also may be formedaround the core or intermediate layer by first forming half shells byinjection molding the compositions again using a heated injection moldthat allows sufficient temperature control to yield the desired halfshell properties. The resulting half shells then may be compressionmolded around the core or core plus intermediate layer. Again, if thehalf shell is partially cured, the additional compression molding orirradiation steps optionally may be tailored to complete the curingprocess to yield the desired layer properties.

Finally, outer or intermediate covers comprising suitable compositionsalso may be formed around the cores using conventional injectionmolding, casting, reaction injection molding, transfer molding,compression molding techniques, or combination of these techniques.

In addition, if radiation is used as a cross-linking agent, then otheradditives can be irradiated following mixing, during forming into a partsuch as the core, intermediate layer, or outer cover of a ball, or afterforming such part.

A preferred method for making golf balls within the scope of the presentinvention involves injection molding a core, intermediate layer, orcover of the composition into a cold mold without inducing heavycross-linking of the unsaturated polymer. The product from this processthen is compression molded to induce partial or full cross-linking ofthe unsaturated polymer by use of thermal energy.

In another preferred method, injection molding is used to inject thecomposition around a core positioned in a mold, in which thermal energyis applied to induce cross-linking. In yet another preferred method, anintermediate layer or a cover of the unsaturated polymer, peptizer, andcross-linking agent can be prepared by injection molding the mixture ashalf shells. The half shells are then positioned around a core andcompression molded. The heat and pressure first melt the composition toseal the two half shells together forming a complete layer. Additionalthermal energy induces cross-linking of the unsaturated polymer.

In another preferred method, half shells of the unsaturated polymer andpeptizer are prepared. The half shells are coated with the cross-linkingagent and compression molded around a core to form a layer and to inducecross-linking. In another preferred method, a layer incorporating theunsaturated polymer and peptizer is positioned around a core to form alayer. The layer then is coated with the cross-linking agent andcompression molded to induce cross-linking. When used to form a coverlayer, a preferred embodiment of the method involves preparing the coverlayer using injection molding and forming dimples on the surface of thecover layer, while inducing full or partial cross-linking of the layerduring injection molding. Alternately, the cover layer can be formedusing injection molding without dimples, after which the cover layer iscompression molded to form dimples and also induce full or partialcross-linking.

IX. Examples

The following examples are provided to illustrate certain features ofworking embodiments of the disclosed invention. A person of ordinaryskill in the art will appreciate that the invention is not limited tothose features exemplified by these working embodiments.

PGA compression, C.O.R., and Shore D hardness were conducted onmaterials and/or golf balls made according to the present disclosureusing the test methods as defined below.

Shore D hardness was measured in accordance with ASTM Test D2240.Compression is measured by applying a spring-loaded force to the sphereto be examined, with a manual instrument (an “Atti gauge”) manufacturedby the Atti Engineering Company of Union City, N.J. This machine,equipped with a Federal Dial Gauge, Model D81-C, employs a calibratedspring under a known load. The sphere to be tested is forced a distanceof 0.2 inch (5 mm) against this spring. If the spring, in turn,compresses 0.2 inch, the compression is rated at 100; if the springcompresses 0.1 inch, the compression value is rated as 0. Thus morecompressible, softer materials will have lower Atti gauge values thanharder, less compressible materials. Compression measured with thisinstrument is also referred to as PGA compression. The approximaterelationship that exists between Atti or PGA compression and Riehlecompression can be expressed as:

(Atti or PGA compression)=(160−Riehle Compression).

Thus, a Riehle compression of 100 would be the same as an Atticompression of 60.

Initial velocity of a golf ball after impact with a golf club isgoverned by the United States Golf Association (“USGA”). The USGArequires that a regulation golf ball can have an initial velocity of nomore than 250 feet per second±2% or 255 feet per second. The USGAinitial velocity limit is related to the ultimate distance that a ballmay travel (280 yards±6%), and is also related to the coefficient ofrestitution (“COR”). The coefficient of restitution is the ratio of therelative velocity between two objects after direct impact to therelative velocity before impact. As a result, the COR can vary from 0 to1, with 1 being equivalent to a completely elastic collision and 0 beingequivalent to a completely inelastic collision. Since a ball's CORdirectly influences the ball's initial velocity after club collision andtravel distance, golf ball manufacturers are interested in thischaracteristic for designing and testing golf balls.

One conventional technique for measuring COR uses a golf ball or golfball subassembly, air cannon, and a stationary steel plate. The steelplate provides an impact surface weighing about 100 pounds or about 45kilograms. A pair of ballistic light screens, which measure ballvelocity, are spaced apart and located between the air cannon and thesteel plate. The ball is fired from the air cannon toward the steelplate over a range of test velocities from 50 ft/s to 180 ft/sec. As theball travels toward the steel plate, it activates each light screen sothat the time at each light screen is measured. This provides anincoming time period proportional to the ball's incoming velocity. Theball impacts the steel plate and rebounds through the light screens,which again measure the time period required to transit between thelight screens. This provides an outgoing transit time periodproportional to the ball's outgoing velocity. The coefficient ofrestitution can be calculated by the ratio of the outgoing transit timeperiod to the incoming transit time period, COR=T_(Out)/T_(in).

Example 1

This example describes compositions that were made using2,3,5,6-tetrachloro-4-pyridinethiol (TCPT), in comparison tocompositions made without using a peptizer, and compositions that weremade using known peptizers, such as pentachlorothiophenol,pentachlorothiophenol, the zinc salt of pentachlorothiophenol (Zn-PCTP),the ammonium salt of pentachlorothiophenol (NH₄—PCTP). A series of ballcores having diameters of 1.48 inches and suitable for use in golf ballswithin the scope of the present invention were prepared. Each of thecores incorporated predominantly cis-1,4-polybutadiene rubber.Additionally, the cores incorporated selected amounts of additionalagents, such as zinc oxide (ZnO), zinc diacrylate (ZDA), and peroxide.Finally, some cores incorporated selected amounts ofpentachlorothiophenol, the zinc salt of pentachlorothiophenol (Zn-PCTP),the ammonium salt (NH₄—PCTP) generated by reaction between PCTP andammonium hydroxide, and 2,3,5,6-tetrachloro-4-pyridinethiol. The coreswere compression molded at 180° C. for 12 minutes. Composition andproperty information for cores made according to this example areprovided in Tables 1-3. The samples were then tested for C.O.R. andcompression after one day and after 5 days.

TABLE 1 No Additive PCTP Zn-PCTP NH₄-PCTP TCPT CC 50 38 38 34 39 COR0.787 0.794 0.797 0.792 0.791 Hardness 41.3 40 38 39.8 40.8 (Shore D)Specific 1.211 1.206 1.205 1.198 1.19 Gravity AFTER 5 DAYS Core 52 39 4236 41 Compression COR 0.787 0.796 0.799 0.793 0.793 Hardness 40.8 38.640.7 38.9 38.8 (Shore D) Specific 1.197 1.19 1.198 1.194 1.195 Gravity

TABLE 2 No Additive PCTP TCPT Core Compression (PGA) 76 60 66 COR 0.8090.813 0.813 Hardness (Shore D) 44.5 45.5 43.6 Specific Gravity 1.1881.178 1.18

TABLE 3 No Additive PCTP TCPT Core Compression (PGA) 64 51 57 COR 0.8030.808 0.806 Hardness (Shore D) 42.3 41.4 41.8 Specific Gravity 1.1751.179 1.177The best results are obtained by maximizing the C.O.R. value whilemaintaining or decreasing Atti compression. The results of the testingindicate that the addition of TCPT increased the COR value relative tono additive used, and substantially maintained the COR relative toPCTP-containing compositions. With respect to core compression (CC), theaddition of a peptizing agent generally decreases CC. But, balls madehaving TCPT had substantially similar or greater core compressionrelative to balls made using PCTP or salts thereof. Being able to use adifferent peptizer and provide substantially similar or improved resultscompared to known balls allows for greater flexibility in making golfballs by expanding composition parameters that allow for adjustingcompression and/or C.O.R.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the invention andshould not be taken as limiting the scope of the invention. Rather, thescope of the invention is defined by the following claims. We thereforeclaim as our invention all that comes within the scope and spirit ofthese claims.

1. A golf ball, comprising: a core made from a polymer core compositioncomprising polybutadiene, a crosslinking agent, and an effective amountof at least one peptizer having a formula

where V-Z independently are carbon or heteroatoms, and at least one ofR₂-R₆ is halogen, with any remaining R₂-R₆ being independently selectedfrom hydrogen, halogen, oxygen-bearing moieties, sulfur-bearingmoieties, or aliphatic groups, and zinc diacrylate; and at least oneouter layer surrounding the core comprising a polymer layer compositioncomprising a polyalkenamer, a crosslinking agent, and an effectiveamount of at least one peptizer according to the formula.
 2. The golfball according to claim 1 comprising a halogenated pyridine peptizer, ahalogenated pyrimidine peptizer, a halogenated diazine peptizer, ahalogenated triazine peptizer, an aromatic halogenated thiol, orcombinations of such peptizers.
 3. The golf ball according to claim 1where at least one peptizer has a formula

where at least one of R₂-R₆ is halogen, with any remaining R₂-R₆ beingindependently selected from hydrogen, halogen, oxygen-bearing moieties,sulfur-bearing moieties, or aliphatic groups.
 4. The golf ball accordingto claim 1 where at least one peptizer has a formula

where R₂-R₆ are independently hydrogen, halogen, oxygen-bearingmoieties, sulfur-bearing moieties or aliphatic groups.
 5. The golf ballaccording to claim 1 where at least one peptizer has a formula

where R₂, R₄ and R₆ independently are hydrogen, halogen, oxygen-bearingmoieties, sulfur-bearing moieties or aliphatic groups.
 6. The golf ballaccording to claim 1 where at least one of R₂-R₆ is —SH, and at leastone of the remaining R₂-R₆ is halogen.
 7. The golf ball according toclaim 1 where at least one peptizer has a formula

where at least one of R₂-R₃ and R₅-R₆ are halogen, with any remainingR₂-R₃ and R₅-R₆ being independently selected from hydrogen or halogen.8. The golf ball according to claim 1 having a core, one or moreintermediate layers, and a cover, the core having a PGA compression offrom about 30 to about 190, the one or more intermediate layers or coverlayer having a thickness of from about 0.01 to about 0.17 inch and aShore D hardness of greater than about
 25. 9. The golf ball according toclaim 1 wherein at least one peptizer is2,3,5,6-tetrachloro-4-pyridinethiol.
 10. The golf ball according toclaim 1, where the crosslinking agent of the core, the polymer layercomposition, or both, comprises a first peroxide crosslinking agent anda second peroxide crosslinking agent.
 11. The golf ball according toclaim 10 wherein each of the first and second peroxide crosslinkingagents has a characteristic decomposition temperature at which 50% ofthe crosslinking agent has decomposed when subjected to thedecomposition temperature for a specified time period (t_(1/2)).
 12. Thegolf ball according to claim 10 wherein the first and second peroxidecrosslinking agents have different characteristic decompositiontemperatures at the same t_(1/2).
 13. The golf ball according to claim10 wherein the first or second peroxide crosslinking agent has att_(1/2)=0.1 hour a decomposition temperature of 138° C.
 14. The golfball according to claim 13 where the crosslinking agent is1,1-bis-(t-butylperoxy)-3,3,5-tri-methylcyclohexane.
 15. The golf ballaccording to claim 10 wherein the first or second peroxide crosslinkingagent has at t_(1/2)=0.1 hour a decomposition temperature of 182° C. 16.The golf ball according to claim 15 where the crosslinking agent is2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3.
 17. The golf ball accordingto claim 10 where the first peroxide crosslinking agent has a firstcharacteristic decomposition temperature less than 150° C., and thesecond peroxide crosslinking agent has a second characteristicdecomposition temperature greater than 150° C.
 18. The golf ballaccording to claim 1 comprising a three-piece golf ball.
 19. The golfball according to claim 1 comprising a four-piece golf ball.
 20. Amethod for making a golf ball, comprising: making a core comprisingpolybutadiene, a crosslinking agent, and an effective amount of at leastone peptizer having a formula

where V-Z independently are carbon or heteroatoms, and at least one ofR₂-R₆ is halogen, with any remaining R₂-R₆ being independently selectedfrom hydrogen, halogen, oxygen-bearing moieties, sulfur-bearingmoieties, or aliphatic groups, and zinc diacrylate; and making a layerabout the core comprising a polymer layer composition comprising apolyalkenamer and an effective amount of at least one peptizer accordingto the formula.